TY  - JOUR
AU  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Čekada, Miha
AU  - Jagličić, Zvonko
AU  - Pregelj, Matej
AU  - Spreitzer, Matjaž
AU  - Panjan, Peter
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12839
AB  - In the literature, a magnetic “easy” axis perpendicular to the film plane at room temperature (i.e., perpendicular magnetic anisotropy - PMA) has been reported in Ni (nickel) layers with thicknesses below ≈15 nm. In this work, we observed room-temperature PMA in a-Si/Ni/a-Si (where a-Si denotes amorphous silicon) thin film structures with nickel layer thicker than 15 nm. Two layered structures were prepared by DC/RF triode sputtering: [a-Si/Ni/a-Si] sandwich structure and [a-Si/Ni/a-Si]5 multilayer structure. The cross sectional STEM revealed uniform Ni layers with thicknesses of ≈17 nm in [a-Si/Ni/a-Si]5 – multilayer and ≈28 nm in [a-Si/Ni/a-Si] – single-layer whereas amorphous Si layers were ≈15 nm and 170 nm thick, respectively. An amorphous Ni–Si interphase was also observed in the layered structures. The XRD showed patterns for fcc-Ni with dominant (111) orientation. No other crystalline phases were observed in the XRD patterns. To our knowledge, there are no literature reports of easy magnetization direction perpendicular to the film plane at room temperature for Ni layers with thickness of ≈28 nm as presented in this work. The origin of PMA in a-Si/Ni/a-Si films may be mainly attributed to the magnetoelastic anisotropy whereas the secondary source of PMA is believed to be the surface anisotropy and magnetocrystalline anisotropy of [111] columnar grains. Amorphous silicon layers (substrate) do not have a well-defined lattice structure like crystalline substrates. Therefore, they do not induce strains in the nickel layers through lattice mismatch as in the case of epitaxy. The strains can be caused by other factors such as diffusion-induced strain, thermal expansion mismatch or intrinsic stresses during the growth process. These results could be important for applications in memory devices, sensors, logic chips, magneto-optic, magneto-electronic and spintronic devices and in fundamental research, as well as first step toward preparation and understanding of the PMA in thick nickel layers.
T2  - Ceramics International
T1  - Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers
VL  - 49
IS  - 19
SP  - 32068
EP  - 32077
DO  - 10.1016/j.ceramint.2023.07.174
ER  - 

@article{
author = "Tadić, Marin and Panjan, Matjaž and Čekada, Miha and Jagličić, Zvonko and Pregelj, Matej and Spreitzer, Matjaž and Panjan, Peter",
year = "2023",
abstract = "In the literature, a magnetic “easy” axis perpendicular to the film plane at room temperature (i.e., perpendicular magnetic anisotropy - PMA) has been reported in Ni (nickel) layers with thicknesses below ≈15 nm. In this work, we observed room-temperature PMA in a-Si/Ni/a-Si (where a-Si denotes amorphous silicon) thin film structures with nickel layer thicker than 15 nm. Two layered structures were prepared by DC/RF triode sputtering: [a-Si/Ni/a-Si] sandwich structure and [a-Si/Ni/a-Si]5 multilayer structure. The cross sectional STEM revealed uniform Ni layers with thicknesses of ≈17 nm in [a-Si/Ni/a-Si]5 – multilayer and ≈28 nm in [a-Si/Ni/a-Si] – single-layer whereas amorphous Si layers were ≈15 nm and 170 nm thick, respectively. An amorphous Ni–Si interphase was also observed in the layered structures. The XRD showed patterns for fcc-Ni with dominant (111) orientation. No other crystalline phases were observed in the XRD patterns. To our knowledge, there are no literature reports of easy magnetization direction perpendicular to the film plane at room temperature for Ni layers with thickness of ≈28 nm as presented in this work. The origin of PMA in a-Si/Ni/a-Si films may be mainly attributed to the magnetoelastic anisotropy whereas the secondary source of PMA is believed to be the surface anisotropy and magnetocrystalline anisotropy of [111] columnar grains. Amorphous silicon layers (substrate) do not have a well-defined lattice structure like crystalline substrates. Therefore, they do not induce strains in the nickel layers through lattice mismatch as in the case of epitaxy. The strains can be caused by other factors such as diffusion-induced strain, thermal expansion mismatch or intrinsic stresses during the growth process. These results could be important for applications in memory devices, sensors, logic chips, magneto-optic, magneto-electronic and spintronic devices and in fundamental research, as well as first step toward preparation and understanding of the PMA in thick nickel layers.",
journal = "Ceramics International",
title = "Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers",
volume = "49",
number = "19",
pages = "32068-32077",
doi = "10.1016/j.ceramint.2023.07.174"
}

Tadić, M., Panjan, M., Čekada, M., Jagličić, Z., Pregelj, M., Spreitzer, M.,& Panjan, P.. (2023). Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers. in Ceramics International, 49(19), 32068-32077.
https://doi.org/10.1016/j.ceramint.2023.07.174

Tadić M, Panjan M, Čekada M, Jagličić Z, Pregelj M, Spreitzer M, Panjan P. Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers. in Ceramics International. 2023;49(19):32068-32077.
doi:10.1016/j.ceramint.2023.07.174 .

Tadić, Marin, Panjan, Matjaž, Čekada, Miha, Jagličić, Zvonko, Pregelj, Matej, Spreitzer, Matjaž, Panjan, Peter, "Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers" in Ceramics International, 49, no. 19 (2023):32068-32077,
https://doi.org/10.1016/j.ceramint.2023.07.174 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Lalatone, Yoann
AU  - Milošević, Irena
AU  - Vučetić Tadić, Biljana
AU  - Lazović, Jelena
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10477
AB  - We investigate synthesis, phase evolution, hollow and porous structure and magnetic properties of quasi-amorphous intermediate phase (QUAIPH) and hematite (α-Fe2O3) nanostructure synthesized by annealing of akaganeite (β-FeOOH) nanorods. It is found that the annealing temperature determines the phase composition of the products, the crystal structure/size dictates the magnetic properties whereas the final nanorod morphology is determined by the starting material. Annealing of β-FeOOH at ∼300 °C resulted in the formation of hollow QUAIPH nanorods. The synthesized material shows low-cytotoxicity, superparamagnetism and good transverse relaxivity, which is rarely reported for QUAIPH. The QUAIPH nanorods started to transform to porous hematite nanostructures at ∼350 °C and phase transformation was completed at 600 °C. During the annealing, the crystal structure changed from monoclinic (akaganeite) to quasi-amorphous and rhombohedral (hematite). Unusually, the crystallite size first decreased (akaganeite → QUAIPH) and then increased (QUAIPH → hematite) during annealing whereas the nanorods retained particle shape. The magnetic properties of the samples changed from antiferromagnetic (akaganeite) to superparamagnetic with blocking temperature TB = 84 K (QUAIPH) and finally to weak-ferromagnetic with the Morin transition at TM = 244 K and high coercivity HC = 1652 Oe (hematite). The low-cytotoxicity and MRI relaxivity (r2 = 5.80 mM−1 s−1 (akaganeite), r2 = 4.31 mM−1 s−1 (QUAIPH) and r2 = 5.17 mM−1 s−1 (hematite)) reveal potential for biomedical applications.
T2  - Advanced Powder Technology
T1  - Magnetic properties, phase evolution, hollow structure and biomedical application of hematite (α-Fe2O3) and QUAIPH
VL  - 33
IS  - 12
SP  - 103847
DO  - 10.1016/j.apt.2022.103847
ER  - 

@article{
author = "Tadić, Marin and Panjan, Matjaž and Lalatone, Yoann and Milošević, Irena and Vučetić Tadić, Biljana and Lazović, Jelena",
year = "2022",
abstract = "We investigate synthesis, phase evolution, hollow and porous structure and magnetic properties of quasi-amorphous intermediate phase (QUAIPH) and hematite (α-Fe2O3) nanostructure synthesized by annealing of akaganeite (β-FeOOH) nanorods. It is found that the annealing temperature determines the phase composition of the products, the crystal structure/size dictates the magnetic properties whereas the final nanorod morphology is determined by the starting material. Annealing of β-FeOOH at ∼300 °C resulted in the formation of hollow QUAIPH nanorods. The synthesized material shows low-cytotoxicity, superparamagnetism and good transverse relaxivity, which is rarely reported for QUAIPH. The QUAIPH nanorods started to transform to porous hematite nanostructures at ∼350 °C and phase transformation was completed at 600 °C. During the annealing, the crystal structure changed from monoclinic (akaganeite) to quasi-amorphous and rhombohedral (hematite). Unusually, the crystallite size first decreased (akaganeite → QUAIPH) and then increased (QUAIPH → hematite) during annealing whereas the nanorods retained particle shape. The magnetic properties of the samples changed from antiferromagnetic (akaganeite) to superparamagnetic with blocking temperature TB = 84 K (QUAIPH) and finally to weak-ferromagnetic with the Morin transition at TM = 244 K and high coercivity HC = 1652 Oe (hematite). The low-cytotoxicity and MRI relaxivity (r2 = 5.80 mM−1 s−1 (akaganeite), r2 = 4.31 mM−1 s−1 (QUAIPH) and r2 = 5.17 mM−1 s−1 (hematite)) reveal potential for biomedical applications.",
journal = "Advanced Powder Technology",
title = "Magnetic properties, phase evolution, hollow structure and biomedical application of hematite (α-Fe2O3) and QUAIPH",
volume = "33",
number = "12",
pages = "103847",
doi = "10.1016/j.apt.2022.103847"
}

Tadić, M., Panjan, M., Lalatone, Y., Milošević, I., Vučetić Tadić, B.,& Lazović, J.. (2022). Magnetic properties, phase evolution, hollow structure and biomedical application of hematite (α-Fe2O3) and QUAIPH. in Advanced Powder Technology, 33(12), 103847.
https://doi.org/10.1016/j.apt.2022.103847

Tadić M, Panjan M, Lalatone Y, Milošević I, Vučetić Tadić B, Lazović J. Magnetic properties, phase evolution, hollow structure and biomedical application of hematite (α-Fe2O3) and QUAIPH. in Advanced Powder Technology. 2022;33(12):103847.
doi:10.1016/j.apt.2022.103847 .

Tadić, Marin, Panjan, Matjaž, Lalatone, Yoann, Milošević, Irena, Vučetić Tadić, Biljana, Lazović, Jelena, "Magnetic properties, phase evolution, hollow structure and biomedical application of hematite (α-Fe2O3) and QUAIPH" in Advanced Powder Technology, 33, no. 12 (2022):103847,
https://doi.org/10.1016/j.apt.2022.103847 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Lazović, Jelena
AU  - Panjan, Matjaž
AU  - Kralj, Slavko
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10189
AB  - Controlled spatial arrangements of superparamagnetic iron oxide nanoparticles (SPIONs) in complex nanostructures determine fine tuning of physico-chemical properties which, in turn, may lead to new practical applications. We report here on newly observed properties of hierarchical SPIONs nanostructure with bundle-like morphology, also known as nanobundles. Colloidal chemical processes and sol-gel synthesis were used for the synthesis of nanobundles, i.e. i) self-assembly of SPIONs into magnetic nanoparticle clusters, ii) their magnetic assembly to the nanochains, and finally iii) formation of bundle-like hierarchical nanostructure. An XRPD measurements show spinel crystal structure of maghemite/magnetite nanoparticles, EDS analysis reveals Fe, Si and O as main elements whereas SEM/TEM analysis show silica-coated magnetic nanoclusters (∼100 nm) and their hierarchical assemblies with bundle-like morphology of ∼8 μm length and ∼1 μm width. TEM analysis revealed core-shell nature of iron oxide nanoparticle clusters with their size of around 80 nm that were coated by an amorphous silica shell with thickness of ∼15 nm. The nanoclusters in the core are constructed of maghemite/magnetite nanoparticle assembly with primary iron oxide nanoparticle size about 10 nm. The magnetization M data as a function of an applied external magnetic field H were successfully fitted by the Langevin function, whence the magnetic moment μp = 19256 μB, and the diameter d = 9.6 nm of nanoparticles were determined. Microsized bundle-like particles are superparamagnetic, magnetically guidable and possess high transverse relaxivity of r2 = 397.8 mM−1s−1. Magnetic properties and such high value of transverse relaxivity holds promise for nanobundles application in MRI imaging (MRI contrast agent), as nanobundles may enhance the magnetic field in their surroundings and enhance proton relaxation processes. Our nanobundles can open new opportunities in the biomedical applications, magnetic separation, photonic crystals and magnetic liquid manipulation and can be inspiration for synthesizing novel self-assembled nanoparticle structures. © 2022 Elsevier Ltd and Techna Group S.r.l.
T2  - Ceramics International
T1  - Hierarchical iron oxide nanocomposite: Bundle-like morphology, magnetic properties and potential biomedical application
SP  - Early view
DO  - 10.1016/j.ceramint.2022.02.145
ER  - 

@article{
author = "Tadić, Marin and Lazović, Jelena and Panjan, Matjaž and Kralj, Slavko",
year = "2022",
abstract = "Controlled spatial arrangements of superparamagnetic iron oxide nanoparticles (SPIONs) in complex nanostructures determine fine tuning of physico-chemical properties which, in turn, may lead to new practical applications. We report here on newly observed properties of hierarchical SPIONs nanostructure with bundle-like morphology, also known as nanobundles. Colloidal chemical processes and sol-gel synthesis were used for the synthesis of nanobundles, i.e. i) self-assembly of SPIONs into magnetic nanoparticle clusters, ii) their magnetic assembly to the nanochains, and finally iii) formation of bundle-like hierarchical nanostructure. An XRPD measurements show spinel crystal structure of maghemite/magnetite nanoparticles, EDS analysis reveals Fe, Si and O as main elements whereas SEM/TEM analysis show silica-coated magnetic nanoclusters (∼100 nm) and their hierarchical assemblies with bundle-like morphology of ∼8 μm length and ∼1 μm width. TEM analysis revealed core-shell nature of iron oxide nanoparticle clusters with their size of around 80 nm that were coated by an amorphous silica shell with thickness of ∼15 nm. The nanoclusters in the core are constructed of maghemite/magnetite nanoparticle assembly with primary iron oxide nanoparticle size about 10 nm. The magnetization M data as a function of an applied external magnetic field H were successfully fitted by the Langevin function, whence the magnetic moment μp = 19256 μB, and the diameter d = 9.6 nm of nanoparticles were determined. Microsized bundle-like particles are superparamagnetic, magnetically guidable and possess high transverse relaxivity of r2 = 397.8 mM−1s−1. Magnetic properties and such high value of transverse relaxivity holds promise for nanobundles application in MRI imaging (MRI contrast agent), as nanobundles may enhance the magnetic field in their surroundings and enhance proton relaxation processes. Our nanobundles can open new opportunities in the biomedical applications, magnetic separation, photonic crystals and magnetic liquid manipulation and can be inspiration for synthesizing novel self-assembled nanoparticle structures. © 2022 Elsevier Ltd and Techna Group S.r.l.",
journal = "Ceramics International",
title = "Hierarchical iron oxide nanocomposite: Bundle-like morphology, magnetic properties and potential biomedical application",
pages = "Early view",
doi = "10.1016/j.ceramint.2022.02.145"
}

Tadić, M., Lazović, J., Panjan, M.,& Kralj, S.. (2022). Hierarchical iron oxide nanocomposite: Bundle-like morphology, magnetic properties and potential biomedical application. in Ceramics International, Early view.
https://doi.org/10.1016/j.ceramint.2022.02.145

Tadić M, Lazović J, Panjan M, Kralj S. Hierarchical iron oxide nanocomposite: Bundle-like morphology, magnetic properties and potential biomedical application. in Ceramics International. 2022;:Early view.
doi:10.1016/j.ceramint.2022.02.145 .

Tadić, Marin, Lazović, Jelena, Panjan, Matjaž, Kralj, Slavko, "Hierarchical iron oxide nanocomposite: Bundle-like morphology, magnetic properties and potential biomedical application" in Ceramics International (2022):Early view,
https://doi.org/10.1016/j.ceramint.2022.02.145 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Vučetić Tadić, Biljana
AU  - Kralj, Slavko
AU  - Lazović, Jelena
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10102
AB  - A porous hematite/alumina nanocomposite is produced by sol-gel combustion synthesis. The XRPD, Raman and FTIR methods show the presence of α-Fe2O3 phase while SEM, TEM, EDS and BET techniques further reveal the formation of porous ellipsoid-like nanostructure of hematite nanoparticles coated by amorphous alumina. Hematite nanoparticles have a size of ~40 nm whereas the porous hematite/alumina nanocomposite particles are ~100 nm in size with characteristic pores of ~7 nm. The M(H) at 300 K exhibits coercivity HC = 293 Oe and magnetization MS = 2.71 emu/g and at 5 K HC = 1150 Oe and MS = 9.25 emu/g. The M(T) under H = 100 Oe shows a bifurcation between ZFC/FC magnetization curves at all measurement temperatures Tirr>350 K (irreversibility temperature) and blocking temperature at TB ~ 305 K. Unexpectedly, the M(T) measurements under H = 10 kOe reveal the suppressed Morin transition at TM = 225 K. The analysis of the results and data from the literature reveal that the porous surface structure of hematite induces the atypical magnetic properties. A magnetic resonance imaging (MRI) properties show the transverse relaxivity rate (r2) of 0.44 mM−1s−1 at 7 T and 1.06 mM−1s−1 at 15.2 T. The investigated nanocomposite particles could be useful in biomedical applications due to their low cytotoxicity and porous nanostructure.
T2  - Ceramics International
T1  - Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications
DO  - 10.1016/j.ceramint.2021.12.209
ER  - 

@article{
author = "Tadić, Marin and Panjan, Matjaž and Vučetić Tadić, Biljana and Kralj, Slavko and Lazović, Jelena",
year = "2021",
abstract = "A porous hematite/alumina nanocomposite is produced by sol-gel combustion synthesis. The XRPD, Raman and FTIR methods show the presence of α-Fe2O3 phase while SEM, TEM, EDS and BET techniques further reveal the formation of porous ellipsoid-like nanostructure of hematite nanoparticles coated by amorphous alumina. Hematite nanoparticles have a size of ~40 nm whereas the porous hematite/alumina nanocomposite particles are ~100 nm in size with characteristic pores of ~7 nm. The M(H) at 300 K exhibits coercivity HC = 293 Oe and magnetization MS = 2.71 emu/g and at 5 K HC = 1150 Oe and MS = 9.25 emu/g. The M(T) under H = 100 Oe shows a bifurcation between ZFC/FC magnetization curves at all measurement temperatures Tirr>350 K (irreversibility temperature) and blocking temperature at TB ~ 305 K. Unexpectedly, the M(T) measurements under H = 10 kOe reveal the suppressed Morin transition at TM = 225 K. The analysis of the results and data from the literature reveal that the porous surface structure of hematite induces the atypical magnetic properties. A magnetic resonance imaging (MRI) properties show the transverse relaxivity rate (r2) of 0.44 mM−1s−1 at 7 T and 1.06 mM−1s−1 at 15.2 T. The investigated nanocomposite particles could be useful in biomedical applications due to their low cytotoxicity and porous nanostructure.",
journal = "Ceramics International",
title = "Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications",
doi = "10.1016/j.ceramint.2021.12.209"
}

Tadić, M., Panjan, M., Vučetić Tadić, B., Kralj, S.,& Lazović, J.. (2021). Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications. in Ceramics International.
https://doi.org/10.1016/j.ceramint.2021.12.209

Tadić M, Panjan M, Vučetić Tadić B, Kralj S, Lazović J. Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications. in Ceramics International. 2021;.
doi:10.1016/j.ceramint.2021.12.209 .

Tadić, Marin, Panjan, Matjaž, Vučetić Tadić, Biljana, Kralj, Slavko, Lazović, Jelena, "Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications" in Ceramics International (2021),
https://doi.org/10.1016/j.ceramint.2021.12.209 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Milošević, Irena
AU  - Kralj, Slavko
AU  - Hanžel, Darko
AU  - Barudžija, Tanja
AU  - Motte, Laurence
AU  - Makovec, Darko
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8824
AB  - A metastable ε-polymorph of iron(III) oxide (ε-Fe2O3) is a very attractive material from the technological, engineering, and scientific points of view. In comparison with other iron oxides, it is characterized by unusual magnetic properties and a giant coercivity of ~20 kOe, which is the largest value among metal oxides. The routine method of ε-Fe2O3 formation is based on the thermal annealing of maghemite (γ-Fe2O3) nanoparticles confined in a silica matrix where the ε-Fe2O3 appears as an intermediate phase between the maghemite and an α-polymorph (α-Fe2O3) hematite (γ→ε→α pathway). In this study, it is demonstrated that the ε→α transformation can be reversed when hematite nanoparticles with an anisotropic hollow morphology are annealed above 600 °C. The observed reversal of the phase stability is explained in terms of an increased nanoparticle surface area and surface energy related to the hollow structure. This study demonstrates the applicability of surface-induced phase transformation to stabilize and control ε-Fe2O3 nanostructures with anisotropic shape and high coercivity ~1600 kA/m that is one of the key properties of functional magnetic materials for information processing and storage. The understanding of ε-Fe2O3 formation mechanism can provide a new viewpoint and guidance for designing metastable polymorphs and applicative properties. © 2020 Acta Materialia Inc.
T2  - Acta Materialia
T1  - Surface-induced reversal of a phase transformation for the synthesis of ε-Fe2O3 nanoparticles with high coercivity
VL  - 188
SP  - 16
EP  - 22
DO  - 10.1016/j.actamat.2020.01.058
ER  - 

@article{
author = "Tadić, Marin and Milošević, Irena and Kralj, Slavko and Hanžel, Darko and Barudžija, Tanja and Motte, Laurence and Makovec, Darko",
year = "2020",
abstract = "A metastable ε-polymorph of iron(III) oxide (ε-Fe2O3) is a very attractive material from the technological, engineering, and scientific points of view. In comparison with other iron oxides, it is characterized by unusual magnetic properties and a giant coercivity of ~20 kOe, which is the largest value among metal oxides. The routine method of ε-Fe2O3 formation is based on the thermal annealing of maghemite (γ-Fe2O3) nanoparticles confined in a silica matrix where the ε-Fe2O3 appears as an intermediate phase between the maghemite and an α-polymorph (α-Fe2O3) hematite (γ→ε→α pathway). In this study, it is demonstrated that the ε→α transformation can be reversed when hematite nanoparticles with an anisotropic hollow morphology are annealed above 600 °C. The observed reversal of the phase stability is explained in terms of an increased nanoparticle surface area and surface energy related to the hollow structure. This study demonstrates the applicability of surface-induced phase transformation to stabilize and control ε-Fe2O3 nanostructures with anisotropic shape and high coercivity ~1600 kA/m that is one of the key properties of functional magnetic materials for information processing and storage. The understanding of ε-Fe2O3 formation mechanism can provide a new viewpoint and guidance for designing metastable polymorphs and applicative properties. © 2020 Acta Materialia Inc.",
journal = "Acta Materialia",
title = "Surface-induced reversal of a phase transformation for the synthesis of ε-Fe2O3 nanoparticles with high coercivity",
volume = "188",
pages = "16-22",
doi = "10.1016/j.actamat.2020.01.058"
}

Tadić, M., Milošević, I., Kralj, S., Hanžel, D., Barudžija, T., Motte, L.,& Makovec, D.. (2020). Surface-induced reversal of a phase transformation for the synthesis of ε-Fe2O3 nanoparticles with high coercivity. in Acta Materialia, 188, 16-22.
https://doi.org/10.1016/j.actamat.2020.01.058

Tadić M, Milošević I, Kralj S, Hanžel D, Barudžija T, Motte L, Makovec D. Surface-induced reversal of a phase transformation for the synthesis of ε-Fe2O3 nanoparticles with high coercivity. in Acta Materialia. 2020;188:16-22.
doi:10.1016/j.actamat.2020.01.058 .

Tadić, Marin, Milošević, Irena, Kralj, Slavko, Hanžel, Darko, Barudžija, Tanja, Motte, Laurence, Makovec, Darko, "Surface-induced reversal of a phase transformation for the synthesis of ε-Fe2O3 nanoparticles with high coercivity" in Acta Materialia, 188 (2020):16-22,
https://doi.org/10.1016/j.actamat.2020.01.058 . .

TY  - JOUR
AU  - Nikolić, Violeta N.
AU  - Tadić, Marin
AU  - Jovanović, Sonja
AU  - Spasojević, Vojislav
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0272884219314166
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8220
AB  - We performed structural and magnetic investigation of Fe3O4/OA nanoparticles prepared by solvothermal method. Based on XRD, TEM and FTIR examination, investigated sample contained monodisperse, 5 nm-sized spherical magnetite nanoparticles coated with oleic acid. Magnetic measurement of the hysteretic curves at 5 K in zero-field cooled (ZFC) and field-cooled (FC) regime confirmed presence of exchange bias effect. ZFC/FC measurements were performed in applied magnetic fields: 10 Oe, 100 Oe, 200 Oe, 500 Oe and 1000 Oe. Zero-field cooled magnetization curves recorded in 10 Oe and 100 Oe exhibited behavior characteristic for low coercivity Nanomaterials. Same sample exposed to the ZFC/FC measurement protocol in 200 Oe, 500 Oe and 1000 Oe showed increase in ZFC magnetization in the certain temperature range. The observed feature is attributed to the local changes in the magnetite electronic structure, occurred through the spin reorientation process. © 2019 Elsevier Ltd and Techna Group S.r.l.
T2  - Ceramics International
T1  - Tracking of the electronic re-ordering in Fe3O4/OA nanoparticles using magnetometry
VL  - 45
IS  - 14
SP  - 17429
EP  - 17437
DO  - 10.1016/j.ceramint.2019.05.303
ER  - 

@article{
author = "Nikolić, Violeta N. and Tadić, Marin and Jovanović, Sonja and Spasojević, Vojislav",
year = "2019",
abstract = "We performed structural and magnetic investigation of Fe3O4/OA nanoparticles prepared by solvothermal method. Based on XRD, TEM and FTIR examination, investigated sample contained monodisperse, 5 nm-sized spherical magnetite nanoparticles coated with oleic acid. Magnetic measurement of the hysteretic curves at 5 K in zero-field cooled (ZFC) and field-cooled (FC) regime confirmed presence of exchange bias effect. ZFC/FC measurements were performed in applied magnetic fields: 10 Oe, 100 Oe, 200 Oe, 500 Oe and 1000 Oe. Zero-field cooled magnetization curves recorded in 10 Oe and 100 Oe exhibited behavior characteristic for low coercivity Nanomaterials. Same sample exposed to the ZFC/FC measurement protocol in 200 Oe, 500 Oe and 1000 Oe showed increase in ZFC magnetization in the certain temperature range. The observed feature is attributed to the local changes in the magnetite electronic structure, occurred through the spin reorientation process. © 2019 Elsevier Ltd and Techna Group S.r.l.",
journal = "Ceramics International",
title = "Tracking of the electronic re-ordering in Fe3O4/OA nanoparticles using magnetometry",
volume = "45",
number = "14",
pages = "17429-17437",
doi = "10.1016/j.ceramint.2019.05.303"
}

Nikolić, V. N., Tadić, M., Jovanović, S.,& Spasojević, V.. (2019). Tracking of the electronic re-ordering in Fe3O4/OA nanoparticles using magnetometry. in Ceramics International, 45(14), 17429-17437.
https://doi.org/10.1016/j.ceramint.2019.05.303

Nikolić VN, Tadić M, Jovanović S, Spasojević V. Tracking of the electronic re-ordering in Fe3O4/OA nanoparticles using magnetometry. in Ceramics International. 2019;45(14):17429-17437.
doi:10.1016/j.ceramint.2019.05.303 .

Nikolić, Violeta N., Tadić, Marin, Jovanović, Sonja, Spasojević, Vojislav, "Tracking of the electronic re-ordering in Fe3O4/OA nanoparticles using magnetometry" in Ceramics International, 45, no. 14 (2019):17429-17437,
https://doi.org/10.1016/j.ceramint.2019.05.303 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Trpkov, Đorđe
AU  - Kopanja, Lazar
AU  - Vojnović, Sandra
AU  - Panjan, Matjaž
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0925838819312587
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8133
AB  - In this work, we present the magnetic and structural properties of α-Fe 2 O 3 nanoparticles synthesized by the hydrothermal synthesis method. XRD, FTIR and Raman spectroscopy indicate that the samples consist of single-phase α-Fe 2 O 3 nanoparticles. A microstructural analysis by TEM and SEM shows: (i) irregular nanoparticles (∼50 nm), (ii) plate-like nanoparticles (with thickness t∼10 nm and diameter d∼50–80 nm) and (iii) microsized ellipsoid 3D superstructures (with length l∼3.5 and diameter d∼1.5 μm) composed of nanosized building blocks (∼50 nm). We used circularity, elongation and convexity measures to quantitatively analyze the shape of the particles. Irregular hematite nanoparticles were synthesized using a water solution of ferric precursor and sodium acetate during the hydrothermal reaction (reaction conditions: T = 180 °C, t = 12 h). The same hydrothermal reaction temperature, reaction duration and ferric precursor (without sodium acetate) were used for synthesizing hematite ellipsoid 3D superstructures. Addition of urea and glycine surfactants in hydrothermal reaction resulted in the formation of nanoplate hematite particles. The role of these surfactants on the structure and morphology of the particles was also investigated. Magnetic measurements at the room temperature displayed a wide range of coercivities, from H C = 73 Oe for irregular nanoparticles, H C = 689 Oe for nanoplates to H C = 2688 Oe for hematite ellipsoid 3D superstructures. The measured coercivity for the ellipsoid superstructure was about 35 times higher than in the case of irregular hematite nanoparticles and about 4 times than the coercivity of hematite nanoplates. Magnetic properties of synthesized samples were related to their structure and morphology. We conclude that shape anisotropy influenced enhancement of the coercivity in hematite nanoplates whereas hematite ellipsoid 3D superstructure (nanoparticle clusters) induced the formation of multidomain magnetic structure and highest coercivity revealing its superior structure for enhanced magnetic properties. The synthesized hematite nanoparticle structures exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating a safe use of these nanoparticles for practical applications. © 2019 Elsevier B.V.
T2  - Journal of Alloys and Compounds
T1  - Hydrothermal synthesis of hematite (α-Fe2O3) nanoparticle forms: Synthesis conditions, structure, particle shape analysis, cytotoxicity and magnetic properties
VL  - 792
SP  - 599
EP  - 609
DO  - 10.1016/j.jallcom.2019.03.414
ER  - 

@article{
author = "Tadić, Marin and Trpkov, Đorđe and Kopanja, Lazar and Vojnović, Sandra and Panjan, Matjaž",
year = "2019",
abstract = "In this work, we present the magnetic and structural properties of α-Fe 2 O 3 nanoparticles synthesized by the hydrothermal synthesis method. XRD, FTIR and Raman spectroscopy indicate that the samples consist of single-phase α-Fe 2 O 3 nanoparticles. A microstructural analysis by TEM and SEM shows: (i) irregular nanoparticles (∼50 nm), (ii) plate-like nanoparticles (with thickness t∼10 nm and diameter d∼50–80 nm) and (iii) microsized ellipsoid 3D superstructures (with length l∼3.5 and diameter d∼1.5 μm) composed of nanosized building blocks (∼50 nm). We used circularity, elongation and convexity measures to quantitatively analyze the shape of the particles. Irregular hematite nanoparticles were synthesized using a water solution of ferric precursor and sodium acetate during the hydrothermal reaction (reaction conditions: T = 180 °C, t = 12 h). The same hydrothermal reaction temperature, reaction duration and ferric precursor (without sodium acetate) were used for synthesizing hematite ellipsoid 3D superstructures. Addition of urea and glycine surfactants in hydrothermal reaction resulted in the formation of nanoplate hematite particles. The role of these surfactants on the structure and morphology of the particles was also investigated. Magnetic measurements at the room temperature displayed a wide range of coercivities, from H C = 73 Oe for irregular nanoparticles, H C = 689 Oe for nanoplates to H C = 2688 Oe for hematite ellipsoid 3D superstructures. The measured coercivity for the ellipsoid superstructure was about 35 times higher than in the case of irregular hematite nanoparticles and about 4 times than the coercivity of hematite nanoplates. Magnetic properties of synthesized samples were related to their structure and morphology. We conclude that shape anisotropy influenced enhancement of the coercivity in hematite nanoplates whereas hematite ellipsoid 3D superstructure (nanoparticle clusters) induced the formation of multidomain magnetic structure and highest coercivity revealing its superior structure for enhanced magnetic properties. The synthesized hematite nanoparticle structures exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating a safe use of these nanoparticles for practical applications. © 2019 Elsevier B.V.",
journal = "Journal of Alloys and Compounds",
title = "Hydrothermal synthesis of hematite (α-Fe2O3) nanoparticle forms: Synthesis conditions, structure, particle shape analysis, cytotoxicity and magnetic properties",
volume = "792",
pages = "599-609",
doi = "10.1016/j.jallcom.2019.03.414"
}

Tadić, M., Trpkov, Đ., Kopanja, L., Vojnović, S.,& Panjan, M.. (2019). Hydrothermal synthesis of hematite (α-Fe2O3) nanoparticle forms: Synthesis conditions, structure, particle shape analysis, cytotoxicity and magnetic properties. in Journal of Alloys and Compounds, 792, 599-609.
https://doi.org/10.1016/j.jallcom.2019.03.414

Tadić M, Trpkov Đ, Kopanja L, Vojnović S, Panjan M. Hydrothermal synthesis of hematite (α-Fe2O3) nanoparticle forms: Synthesis conditions, structure, particle shape analysis, cytotoxicity and magnetic properties. in Journal of Alloys and Compounds. 2019;792:599-609.
doi:10.1016/j.jallcom.2019.03.414 .

Tadić, Marin, Trpkov, Đorđe, Kopanja, Lazar, Vojnović, Sandra, Panjan, Matjaž, "Hydrothermal synthesis of hematite (α-Fe2O3) nanoparticle forms: Synthesis conditions, structure, particle shape analysis, cytotoxicity and magnetic properties" in Journal of Alloys and Compounds, 792 (2019):599-609,
https://doi.org/10.1016/j.jallcom.2019.03.414 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Lončar, Boris B.
AU  - Žunić, Dragiša
AU  - Tadić, Marin
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8590
AB  - The goal of the nanoparticle synthesis is, first of all, the production of nanoparticles that will be more similar in size and shape. This is very important for the possibility of studying and applying nanomaterials because of their characteristics that are very sensitive to size and shape such as, for example, magnetic properties. In this paper, we propose the shape analysis of the nanoparticles using three shape descriptors – elongation, convexity and circularity. Experimental results were obtained by using TEM images of hematite nanoparticles that were, first of all, subjected to segmentation in order to obtain isolated nanoparticles, and then the values of elongation, convexity and circularity were measured. Convexity C x ( S ) is regarded as the ratio between shape’s area and area of the its convex hull. The convexity measure defines the degree to which a shape differs from a convex shape while the circularity measure defines the degree to which a shape differs from an ideal circle. The range of convexity and circularity values is (0, 1], while the range of elongation values is [1, ∞). The circle has lowest elongation (ε = 1), while it has biggest convexity and circularity values ( C x = 1; C = 1). The measures ε( S ), C x ( S ), C ( S ) proposed and used in the experiment have the few desirable properties and give intuitively expected results. None of the measures is good enough to describe all the shapes, and therefore it is suggested to use a variety of measures so that the shapes can be described better and then classify and control during the synthesis process.
T2  - Journal of Electrical Engineering
T1  - Nanoparticle shapes: Quantification by elongation, convexity and circularity measures
VL  - 70
IS  - 7
SP  - 44
EP  - 50
DO  - 10.2478/jee-2019-0040
ER  - 

@article{
author = "Kopanja, Lazar and Lončar, Boris B. and Žunić, Dragiša and Tadić, Marin",
year = "2019",
abstract = "The goal of the nanoparticle synthesis is, first of all, the production of nanoparticles that will be more similar in size and shape. This is very important for the possibility of studying and applying nanomaterials because of their characteristics that are very sensitive to size and shape such as, for example, magnetic properties. In this paper, we propose the shape analysis of the nanoparticles using three shape descriptors – elongation, convexity and circularity. Experimental results were obtained by using TEM images of hematite nanoparticles that were, first of all, subjected to segmentation in order to obtain isolated nanoparticles, and then the values of elongation, convexity and circularity were measured. Convexity C x ( S ) is regarded as the ratio between shape’s area and area of the its convex hull. The convexity measure defines the degree to which a shape differs from a convex shape while the circularity measure defines the degree to which a shape differs from an ideal circle. The range of convexity and circularity values is (0, 1], while the range of elongation values is [1, ∞). The circle has lowest elongation (ε = 1), while it has biggest convexity and circularity values ( C x = 1; C = 1). The measures ε( S ), C x ( S ), C ( S ) proposed and used in the experiment have the few desirable properties and give intuitively expected results. None of the measures is good enough to describe all the shapes, and therefore it is suggested to use a variety of measures so that the shapes can be described better and then classify and control during the synthesis process.",
journal = "Journal of Electrical Engineering",
title = "Nanoparticle shapes: Quantification by elongation, convexity and circularity measures",
volume = "70",
number = "7",
pages = "44-50",
doi = "10.2478/jee-2019-0040"
}

Kopanja, L., Lončar, B. B., Žunić, D.,& Tadić, M.. (2019). Nanoparticle shapes: Quantification by elongation, convexity and circularity measures. in Journal of Electrical Engineering, 70(7), 44-50.
https://doi.org/10.2478/jee-2019-0040

Kopanja L, Lončar BB, Žunić D, Tadić M. Nanoparticle shapes: Quantification by elongation, convexity and circularity measures. in Journal of Electrical Engineering. 2019;70(7):44-50.
doi:10.2478/jee-2019-0040 .

Kopanja, Lazar, Lončar, Boris B., Žunić, Dragiša, Tadić, Marin, "Nanoparticle shapes: Quantification by elongation, convexity and circularity measures" in Journal of Electrical Engineering, 70, no. 7 (2019):44-50,
https://doi.org/10.2478/jee-2019-0040 . .

TY  - JOUR
AU  - Ndioukane, Rémi
AU  - Touré, Moussa
AU  - Kobor, Diouma
AU  - Lalatonne, Yoann
AU  - Motte, Laurence
AU  - Lebrun, Laurent
AU  - Tadić, Marin
AU  - Wilhelm, Fabrice
PY  - 2019
UR  - http://stacks.iop.org/0295-5075/125/i=4/a=47004?key=crossref.48239a40f1584f88e0b245c5ffbf4d74
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8219
AB  - In this work we show the size-dependent ferromagnetic behavior of undoped and Mndoped PZN-4.5PT single crystals, consequently their multiferroic one Undoped single crystals were tamisized and three different sizes powders were investigated showing a size dependence in such ferroelectric materials while no magnetism is observed for the non-oriented and oriented bulk single crystals. The results show the existence of an optimized grain sizes range (45 μm . D . 63 μm) in which the magnetism is the highest (around 0.08 emu/g). It is found that the maximum value of the relative strain decreases from 0.25% for undoped crystals to 0.20% for Mn-doped ones. The remanent magnetization Mr and coercivity (Hc) were found equal, respectively, to 2×10-4 emu/g and 63 Oe for undoped and, 7×10-4 emu/g and 66 Oe for Mn-doped PZN-4.5PT, indicating that PZN-4.5PT particles possessed weak ferromagnetic behavior. Mn doping increases highly the spontaneous magnetization from 7.5 × 10-3 emu/g to 1.0×10-3 emu/g, respectively for undoped and Mn-doped nanoparticles. © 2019 EPLA.
T2  - Europhysics Letters / EPL
T1  - Ferromagnetism evidence and size dependence in ferroelectric PZN-4.5PT nanoparticles
VL  - 125
IS  - 4
SP  - 47004
DO  - 10.1209/0295-5075/125/47004
ER  - 

@article{
author = "Ndioukane, Rémi and Touré, Moussa and Kobor, Diouma and Lalatonne, Yoann and Motte, Laurence and Lebrun, Laurent and Tadić, Marin and Wilhelm, Fabrice",
year = "2019",
abstract = "In this work we show the size-dependent ferromagnetic behavior of undoped and Mndoped PZN-4.5PT single crystals, consequently their multiferroic one Undoped single crystals were tamisized and three different sizes powders were investigated showing a size dependence in such ferroelectric materials while no magnetism is observed for the non-oriented and oriented bulk single crystals. The results show the existence of an optimized grain sizes range (45 μm . D . 63 μm) in which the magnetism is the highest (around 0.08 emu/g). It is found that the maximum value of the relative strain decreases from 0.25% for undoped crystals to 0.20% for Mn-doped ones. The remanent magnetization Mr and coercivity (Hc) were found equal, respectively, to 2×10-4 emu/g and 63 Oe for undoped and, 7×10-4 emu/g and 66 Oe for Mn-doped PZN-4.5PT, indicating that PZN-4.5PT particles possessed weak ferromagnetic behavior. Mn doping increases highly the spontaneous magnetization from 7.5 × 10-3 emu/g to 1.0×10-3 emu/g, respectively for undoped and Mn-doped nanoparticles. © 2019 EPLA.",
journal = "Europhysics Letters / EPL",
title = "Ferromagnetism evidence and size dependence in ferroelectric PZN-4.5PT nanoparticles",
volume = "125",
number = "4",
pages = "47004",
doi = "10.1209/0295-5075/125/47004"
}

Ndioukane, R., Touré, M., Kobor, D., Lalatonne, Y., Motte, L., Lebrun, L., Tadić, M.,& Wilhelm, F.. (2019). Ferromagnetism evidence and size dependence in ferroelectric PZN-4.5PT nanoparticles. in Europhysics Letters / EPL, 125(4), 47004.
https://doi.org/10.1209/0295-5075/125/47004

Ndioukane R, Touré M, Kobor D, Lalatonne Y, Motte L, Lebrun L, Tadić M, Wilhelm F. Ferromagnetism evidence and size dependence in ferroelectric PZN-4.5PT nanoparticles. in Europhysics Letters / EPL. 2019;125(4):47004.
doi:10.1209/0295-5075/125/47004 .

Ndioukane, Rémi, Touré, Moussa, Kobor, Diouma, Lalatonne, Yoann, Motte, Laurence, Lebrun, Laurent, Tadić, Marin, Wilhelm, Fabrice, "Ferromagnetism evidence and size dependence in ferroelectric PZN-4.5PT nanoparticles" in Europhysics Letters / EPL, 125, no. 4 (2019):47004,
https://doi.org/10.1209/0295-5075/125/47004 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Lalatonne, Yoann
AU  - Motte, Laurence
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0169433219301138
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8033
AB  - Investigation and synthesis of anisotropic magnetic nanostructures, such as wires, rods, fibers, tubes and chains, is an important field of research due to the beneficial properties and great potential for practical applications ranging from magnetic data storage to biomedicine. Silica coated iron oxide nanochains of length up to 1 μm and diameter ∼80–100 nm have been synthesized by the simultaneous magnetic assembly of superparamagnetic iron oxide nanoparticle clusters (SNCs) as links (viz. maghemite, γ-Fe2O3) and the fixation of the assembled SNCs with an additional layer of deposited silica. We reveal that is possible to achieve either superparamagnetic or ferromagnetic behavior with the nanochains depending only on their physical orientation. The superparamagnetic behavior is observed for random orientation of nanochains whereas ferromagnetic properties (HC ≈ 100 Oe) come to the fore when the orientation is mainly parallel. These peculiar magnetic properties can be related to: (1) the specific size, which is ∼9 nm, of primary building blocks of the nanochains, i.e. of maghemite nanoparticles; (2) to the anisotropic chain-like shape of the particles; and (3) to inter-particle interactions. Large pore volume and pore size of silica shell as well as good colloidal stability and magnetic responsiveness of such nanochains enable applications in biomedicine. © 2019 Elsevier B.V.
T2  - Applied Surface Science
T1  - Iron oxide nanochains coated with silica: Synthesis, surface effects and magnetic properties
VL  - 476
SP  - 641
EP  - 646
DO  - 10.1016/j.apsusc.2019.01.098
ER  - 

@article{
author = "Tadić, Marin and Kralj, Slavko and Lalatonne, Yoann and Motte, Laurence",
year = "2019",
abstract = "Investigation and synthesis of anisotropic magnetic nanostructures, such as wires, rods, fibers, tubes and chains, is an important field of research due to the beneficial properties and great potential for practical applications ranging from magnetic data storage to biomedicine. Silica coated iron oxide nanochains of length up to 1 μm and diameter ∼80–100 nm have been synthesized by the simultaneous magnetic assembly of superparamagnetic iron oxide nanoparticle clusters (SNCs) as links (viz. maghemite, γ-Fe2O3) and the fixation of the assembled SNCs with an additional layer of deposited silica. We reveal that is possible to achieve either superparamagnetic or ferromagnetic behavior with the nanochains depending only on their physical orientation. The superparamagnetic behavior is observed for random orientation of nanochains whereas ferromagnetic properties (HC ≈ 100 Oe) come to the fore when the orientation is mainly parallel. These peculiar magnetic properties can be related to: (1) the specific size, which is ∼9 nm, of primary building blocks of the nanochains, i.e. of maghemite nanoparticles; (2) to the anisotropic chain-like shape of the particles; and (3) to inter-particle interactions. Large pore volume and pore size of silica shell as well as good colloidal stability and magnetic responsiveness of such nanochains enable applications in biomedicine. © 2019 Elsevier B.V.",
journal = "Applied Surface Science",
title = "Iron oxide nanochains coated with silica: Synthesis, surface effects and magnetic properties",
volume = "476",
pages = "641-646",
doi = "10.1016/j.apsusc.2019.01.098"
}

Tadić, M., Kralj, S., Lalatonne, Y.,& Motte, L.. (2019). Iron oxide nanochains coated with silica: Synthesis, surface effects and magnetic properties. in Applied Surface Science, 476, 641-646.
https://doi.org/10.1016/j.apsusc.2019.01.098

Tadić M, Kralj S, Lalatonne Y, Motte L. Iron oxide nanochains coated with silica: Synthesis, surface effects and magnetic properties. in Applied Surface Science. 2019;476:641-646.
doi:10.1016/j.apsusc.2019.01.098 .

Tadić, Marin, Kralj, Slavko, Lalatonne, Yoann, Motte, Laurence, "Iron oxide nanochains coated with silica: Synthesis, surface effects and magnetic properties" in Applied Surface Science, 476 (2019):641-646,
https://doi.org/10.1016/j.apsusc.2019.01.098 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Kopanja, Lazar
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S1044580318323763
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8005
AB  - We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe2O3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (–NH2) and carboxyl groups (–COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M(H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μp = 20,526 μB for sphere-like nanoparticle clusters and μp = 20,767 μB for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). © 2018
T2  - Materials Characterization
T1  - Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains
VL  - 148
SP  - 123
EP  - 133
DO  - 10.1016/j.matchar.2018.12.014
ER  - 

@article{
author = "Tadić, Marin and Kralj, Slavko and Kopanja, Lazar",
year = "2019",
abstract = "We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe2O3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (–NH2) and carboxyl groups (–COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M(H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μp = 20,526 μB for sphere-like nanoparticle clusters and μp = 20,767 μB for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). © 2018",
journal = "Materials Characterization",
title = "Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains",
volume = "148",
pages = "123-133",
doi = "10.1016/j.matchar.2018.12.014"
}

Tadić, M., Kralj, S.,& Kopanja, L.. (2019). Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains. in Materials Characterization, 148, 123-133.
https://doi.org/10.1016/j.matchar.2018.12.014

Tadić M, Kralj S, Kopanja L. Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains. in Materials Characterization. 2019;148:123-133.
doi:10.1016/j.matchar.2018.12.014 .

Tadić, Marin, Kralj, Slavko, Kopanja, Lazar, "Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains" in Materials Characterization, 148 (2019):123-133,
https://doi.org/10.1016/j.matchar.2018.12.014 . .

TY  - JOUR
AU  - Trpkov, Đorđe
AU  - Panjan, Matjaž
AU  - Kopanja, Lazar
AU  - Tadić, Marin
PY  - 2018
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0169433218317872
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7770
AB  - We report on glycine-free and glycine-assisted hydrothermal synthesis of microsized superstructures composed of self-assembled hematite nanoparticles. An X-ray powder diffraction measurements of the samples confirm good crystallization of the hematite nanoparticles with hydrothermal reaction time-dependent crystallite sizes in a range from ∼15 nm (45 h) to ∼26 nm (90 h). The FTIR and Raman spectroscopy confirm hematite structure, whereas TEM measurements reveal nanoparticle sub-units (subparticles). The computational analyses of particle shape show that the addition of glycine surfactant in hydrothermal reaction leads to more spherical shape of hematite hierarchical structures and smaller sizes. We found strong coercivity increases (up to ∼3 times) in the samples synthesized in the presence of glycine. The coercivity values from HC = 1305 Oe (mushroom-like shape synthesized by glycine-free hydrothermal reaction) to HC = 3725 Oe (sphere-like shape synthesized by glycine-assisted hydrothermal reaction) were obtained at 300 K. These results and their comparison with other described in the literature (e.g. bulk, wires, urchin-like, rods, tubes, plates, star-like, dendrites, platelets, irregular, nanocolumns, spindles, disks hematites, etc.) reveal that the hematite superstructures possess good magnetic properties. We propose that the glycine, oriented subparticles, exchange and dipole-dipole interactions may play an important role in the development of magnetic properties.
T2  - Applied Surface Science
T1  - Hydrothermal synthesis, morphology, magnetic properties and self-assembly of hierarchical α-Fe2O3 (hematite) mushroom-, cube- and sphere-like superstructures
VL  - 457
SP  - 427
EP  - 438
DO  - 10.1016/j.apsusc.2018.06.224
ER  - 

@article{
author = "Trpkov, Đorđe and Panjan, Matjaž and Kopanja, Lazar and Tadić, Marin",
year = "2018",
abstract = "We report on glycine-free and glycine-assisted hydrothermal synthesis of microsized superstructures composed of self-assembled hematite nanoparticles. An X-ray powder diffraction measurements of the samples confirm good crystallization of the hematite nanoparticles with hydrothermal reaction time-dependent crystallite sizes in a range from ∼15 nm (45 h) to ∼26 nm (90 h). The FTIR and Raman spectroscopy confirm hematite structure, whereas TEM measurements reveal nanoparticle sub-units (subparticles). The computational analyses of particle shape show that the addition of glycine surfactant in hydrothermal reaction leads to more spherical shape of hematite hierarchical structures and smaller sizes. We found strong coercivity increases (up to ∼3 times) in the samples synthesized in the presence of glycine. The coercivity values from HC = 1305 Oe (mushroom-like shape synthesized by glycine-free hydrothermal reaction) to HC = 3725 Oe (sphere-like shape synthesized by glycine-assisted hydrothermal reaction) were obtained at 300 K. These results and their comparison with other described in the literature (e.g. bulk, wires, urchin-like, rods, tubes, plates, star-like, dendrites, platelets, irregular, nanocolumns, spindles, disks hematites, etc.) reveal that the hematite superstructures possess good magnetic properties. We propose that the glycine, oriented subparticles, exchange and dipole-dipole interactions may play an important role in the development of magnetic properties.",
journal = "Applied Surface Science",
title = "Hydrothermal synthesis, morphology, magnetic properties and self-assembly of hierarchical α-Fe2O3 (hematite) mushroom-, cube- and sphere-like superstructures",
volume = "457",
pages = "427-438",
doi = "10.1016/j.apsusc.2018.06.224"
}

Trpkov, Đ., Panjan, M., Kopanja, L.,& Tadić, M.. (2018). Hydrothermal synthesis, morphology, magnetic properties and self-assembly of hierarchical α-Fe2O3 (hematite) mushroom-, cube- and sphere-like superstructures. in Applied Surface Science, 457, 427-438.
https://doi.org/10.1016/j.apsusc.2018.06.224

Trpkov Đ, Panjan M, Kopanja L, Tadić M. Hydrothermal synthesis, morphology, magnetic properties and self-assembly of hierarchical α-Fe2O3 (hematite) mushroom-, cube- and sphere-like superstructures. in Applied Surface Science. 2018;457:427-438.
doi:10.1016/j.apsusc.2018.06.224 .

Trpkov, Đorđe, Panjan, Matjaž, Kopanja, Lazar, Tadić, Marin, "Hydrothermal synthesis, morphology, magnetic properties and self-assembly of hierarchical α-Fe2O3 (hematite) mushroom-, cube- and sphere-like superstructures" in Applied Surface Science, 457 (2018):427-438,
https://doi.org/10.1016/j.apsusc.2018.06.224 . .

TY  - CONF
AU  - Nikolić, Violeta N.
AU  - Tadić, Marin
AU  - Mraković, Ana Đ.
AU  - Spasojević, Vojislav
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7850
AB  - Nano iron oxides have been intensively investigated due to their various potential biomedical applications. ε-Fe2O3 phase exerted internal coercivity value up to ~20 kOe, high Curie temperature (Tc= 510 K), and magnetoelectric character. Accordingly, epsilon phase is recognized as a suitable material for medical spintronic biosensors production, that present important part for the lab-on-a-chip systems. Noteworthy, ε-Fe2O3 phase exerts peculiar magnetic behavior. To get better insight into the magnetism of this material, ε-Fe2O3/SiO2 sample was prepared by the combination of the sol-gel synthesis and microemulsion method (Tann=1050 °C, tann= 4h). Afterwards, the sample was exposed to post-annealing treatment at 100 °C and 200 °C. Synthesized material was preliminary examined by XRD and SQUID techniques. Coercivity changes, induced by the post-annealing temperature oscillations, were monitored by hysteretic measurements. Sample annealed at 1050 °C for 4h, showed coercivity ~20 kOe. The same sample performed to the post-annealing treatment at 100 °C, exerted significantly decreased coercivity (~1600 Oe). Further rise of the post-annealing temperature (200 °C) resulted in the increased coercivity ~15 kOe. Obtained study showed that there is insufficient knowledge concerning the ε-Fe2O3 coercivity changes of the polymorph. The more detailed investigation will be conducted, in order to advance the control of the epsilon phase magnetic properties. © 2018 TANGER Ltd. All Rights Reserved.
C3  - NANOCON 2017 - Conference Proceedings, 9th International Conference on Nanomaterials - Research and Application
T1  - Unusual temperature dependence of coercivity in ε-Fe2O3 phase
VL  - 2017-October
SP  - 27
EP  - 32
UR  - https://hdl.handle.net/21.15107/rcub_vinar_7850
ER  - 

@conference{
author = "Nikolić, Violeta N. and Tadić, Marin and Mraković, Ana Đ. and Spasojević, Vojislav",
year = "2018",
abstract = "Nano iron oxides have been intensively investigated due to their various potential biomedical applications. ε-Fe2O3 phase exerted internal coercivity value up to ~20 kOe, high Curie temperature (Tc= 510 K), and magnetoelectric character. Accordingly, epsilon phase is recognized as a suitable material for medical spintronic biosensors production, that present important part for the lab-on-a-chip systems. Noteworthy, ε-Fe2O3 phase exerts peculiar magnetic behavior. To get better insight into the magnetism of this material, ε-Fe2O3/SiO2 sample was prepared by the combination of the sol-gel synthesis and microemulsion method (Tann=1050 °C, tann= 4h). Afterwards, the sample was exposed to post-annealing treatment at 100 °C and 200 °C. Synthesized material was preliminary examined by XRD and SQUID techniques. Coercivity changes, induced by the post-annealing temperature oscillations, were monitored by hysteretic measurements. Sample annealed at 1050 °C for 4h, showed coercivity ~20 kOe. The same sample performed to the post-annealing treatment at 100 °C, exerted significantly decreased coercivity (~1600 Oe). Further rise of the post-annealing temperature (200 °C) resulted in the increased coercivity ~15 kOe. Obtained study showed that there is insufficient knowledge concerning the ε-Fe2O3 coercivity changes of the polymorph. The more detailed investigation will be conducted, in order to advance the control of the epsilon phase magnetic properties. © 2018 TANGER Ltd. All Rights Reserved.",
journal = "NANOCON 2017 - Conference Proceedings, 9th International Conference on Nanomaterials - Research and Application",
title = "Unusual temperature dependence of coercivity in ε-Fe2O3 phase",
volume = "2017-October",
pages = "27-32",
url = "https://hdl.handle.net/21.15107/rcub_vinar_7850"
}

Nikolić, V. N., Tadić, M., Mraković, A. Đ.,& Spasojević, V.. (2018). Unusual temperature dependence of coercivity in ε-Fe2O3 phase. in NANOCON 2017 - Conference Proceedings, 9th International Conference on Nanomaterials - Research and Application, 2017-October, 27-32.
https://hdl.handle.net/21.15107/rcub_vinar_7850

Nikolić VN, Tadić M, Mraković AĐ, Spasojević V. Unusual temperature dependence of coercivity in ε-Fe2O3 phase. in NANOCON 2017 - Conference Proceedings, 9th International Conference on Nanomaterials - Research and Application. 2018;2017-October:27-32.
https://hdl.handle.net/21.15107/rcub_vinar_7850 .

Nikolić, Violeta N., Tadić, Marin, Mraković, Ana Đ., Spasojević, Vojislav, "Unusual temperature dependence of coercivity in ε-Fe2O3 phase" in NANOCON 2017 - Conference Proceedings, 9th International Conference on Nanomaterials - Research and Application, 2017-October (2018):27-32,
https://hdl.handle.net/21.15107/rcub_vinar_7850 .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Žunić, Joviša
PY  - 2018
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0272884218308812
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7917
AB  - Due to advances in electron microscopy and to the development of novel nanoparticle structures with different morphologies and the dependence of physical properties on the nanoparticle morphology, there is a need for a more precise analysis of nanoparticle structure and morphology. That should provide a simple and unambiguous comparison of nanoparticles' shapes and of material properties that depend on the shape, which has been lacking thus far. Here we study nanochains consisting of silica-coated iron oxide (maghemite, gamma-Fe2O3) nanoparticle clusters covered by an additional layer of silica (core-shell structure). We have developed an algorithm for image segmentation and a quantitative analysis of nanochain shape from real TEM images. To that end we used two distinct measures of circularity and elongation measure (the aspect ratio measure). We show that the relative position and the area of the links, as well as the links' shape lead to significant differences in the measured aspect ratio of the entire nanochain (substantially influence the elongation of nanochains). We have also analyzed the core-shell structures in nanochains, and computed the shell's share in the overall area of observed nanochains. A Matlab code was developed and used for the computation of the elongation measure of shapes appearing in electron microscopy images. Here we have investigated magnetic properties of synthetic nanochains, that revealed superparamagnetic behavior at room temperature (SPION) with the possibility of tuning the magnetization values (approx. from 19 to 46 emu/g). We have compared of magnetization M(H) curves of the anisotropic nanochains and of isotropic nanoparticle (nanochain links), with the conclusion that the nanochains have a higher magnetic susceptibility, which fact can be understood as a consequence of their anisotropic shapes. The nanochains may be applied in biomedicine and magnetic separation, due to their morphology and magnetic properties.
T2  - Ceramics International
T1  - Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs
VL  - 44
IS  - 11
SP  - 12340
EP  - 12351
DO  - 10.1016/j.ceramint.2018.04.021
ER  - 

@article{
author = "Kopanja, Lazar and Tadić, Marin and Kralj, Slavko and Žunić, Joviša",
year = "2018",
abstract = "Due to advances in electron microscopy and to the development of novel nanoparticle structures with different morphologies and the dependence of physical properties on the nanoparticle morphology, there is a need for a more precise analysis of nanoparticle structure and morphology. That should provide a simple and unambiguous comparison of nanoparticles' shapes and of material properties that depend on the shape, which has been lacking thus far. Here we study nanochains consisting of silica-coated iron oxide (maghemite, gamma-Fe2O3) nanoparticle clusters covered by an additional layer of silica (core-shell structure). We have developed an algorithm for image segmentation and a quantitative analysis of nanochain shape from real TEM images. To that end we used two distinct measures of circularity and elongation measure (the aspect ratio measure). We show that the relative position and the area of the links, as well as the links' shape lead to significant differences in the measured aspect ratio of the entire nanochain (substantially influence the elongation of nanochains). We have also analyzed the core-shell structures in nanochains, and computed the shell's share in the overall area of observed nanochains. A Matlab code was developed and used for the computation of the elongation measure of shapes appearing in electron microscopy images. Here we have investigated magnetic properties of synthetic nanochains, that revealed superparamagnetic behavior at room temperature (SPION) with the possibility of tuning the magnetization values (approx. from 19 to 46 emu/g). We have compared of magnetization M(H) curves of the anisotropic nanochains and of isotropic nanoparticle (nanochain links), with the conclusion that the nanochains have a higher magnetic susceptibility, which fact can be understood as a consequence of their anisotropic shapes. The nanochains may be applied in biomedicine and magnetic separation, due to their morphology and magnetic properties.",
journal = "Ceramics International",
title = "Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs",
volume = "44",
number = "11",
pages = "12340-12351",
doi = "10.1016/j.ceramint.2018.04.021"
}

Kopanja, L., Tadić, M., Kralj, S.,& Žunić, J.. (2018). Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs. in Ceramics International, 44(11), 12340-12351.
https://doi.org/10.1016/j.ceramint.2018.04.021

Kopanja L, Tadić M, Kralj S, Žunić J. Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs. in Ceramics International. 2018;44(11):12340-12351.
doi:10.1016/j.ceramint.2018.04.021 .

Kopanja, Lazar, Tadić, Marin, Kralj, Slavko, Žunić, Joviša, "Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs" in Ceramics International, 44, no. 11 (2018):12340-12351,
https://doi.org/10.1016/j.ceramint.2018.04.021 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Kovačević, Zorana
AU  - Tadić, Marin
AU  - Žužek, Monika Cecilija
AU  - Vrecl, Milka
AU  - Frangež, Robert
PY  - 2018
UR  - http://link.springer.com/10.1007/s00418-018-1670-0
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7762
AB  - Detailed shape analysis of cells is important to better understand the physiological mechanisms of toxins and determine their effects on cell morphology. This study aimed to develop a procedure for accurate morphological analysis of cell shape and use it as a tool to estimate toxin activity. With the aim of optimizing the method of cell morphology analysis, we determined the influence of ostreolysin A and pleurotolysin B complex (OlyA/PlyB) on the morphology of murine neuronal NG108-15 cells. A computational method was introduced and successfully applied to quantify morphological attributes of the NG108-15 cell line before and after 30 and 60 min exposure to OlyA/PlyB using confocal microscopy. The modified circularity measure (Formula presented.) for shape analysis was applied, which defines the degree to which the shape of the neuron differs from a perfect circle. It enables better detection of small changes in the shape of cells, making the outcome easily detectable numerically. Additionally, we analyzed the influence of OlyA/PlyB on the cell area, allowing us to detect the cells with blebs. This is important because the formation of plasma membrane protrusions such as blebs often reflects cell injury that leads to necrotic cell death. In summary, we offer a novel analytical method of neuronal cell shape analysis and its correlation with the toxic effects of the pore-forming OlyA/PlyB toxin in situ.
T2  - Histochemistry and Cell Biology
T1  - Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex
VL  - 150
IS  - 1
SP  - 93
EP  - 102
DO  - 10.1007/s00418-018-1670-0
ER  - 

@article{
author = "Kopanja, Lazar and Kovačević, Zorana and Tadić, Marin and Žužek, Monika Cecilija and Vrecl, Milka and Frangež, Robert",
year = "2018",
abstract = "Detailed shape analysis of cells is important to better understand the physiological mechanisms of toxins and determine their effects on cell morphology. This study aimed to develop a procedure for accurate morphological analysis of cell shape and use it as a tool to estimate toxin activity. With the aim of optimizing the method of cell morphology analysis, we determined the influence of ostreolysin A and pleurotolysin B complex (OlyA/PlyB) on the morphology of murine neuronal NG108-15 cells. A computational method was introduced and successfully applied to quantify morphological attributes of the NG108-15 cell line before and after 30 and 60 min exposure to OlyA/PlyB using confocal microscopy. The modified circularity measure (Formula presented.) for shape analysis was applied, which defines the degree to which the shape of the neuron differs from a perfect circle. It enables better detection of small changes in the shape of cells, making the outcome easily detectable numerically. Additionally, we analyzed the influence of OlyA/PlyB on the cell area, allowing us to detect the cells with blebs. This is important because the formation of plasma membrane protrusions such as blebs often reflects cell injury that leads to necrotic cell death. In summary, we offer a novel analytical method of neuronal cell shape analysis and its correlation with the toxic effects of the pore-forming OlyA/PlyB toxin in situ.",
journal = "Histochemistry and Cell Biology",
title = "Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex",
volume = "150",
number = "1",
pages = "93-102",
doi = "10.1007/s00418-018-1670-0"
}

Kopanja, L., Kovačević, Z., Tadić, M., Žužek, M. C., Vrecl, M.,& Frangež, R.. (2018). Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex. in Histochemistry and Cell Biology, 150(1), 93-102.
https://doi.org/10.1007/s00418-018-1670-0

Kopanja L, Kovačević Z, Tadić M, Žužek MC, Vrecl M, Frangež R. Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex. in Histochemistry and Cell Biology. 2018;150(1):93-102.
doi:10.1007/s00418-018-1670-0 .

Kopanja, Lazar, Kovačević, Zorana, Tadić, Marin, Žužek, Monika Cecilija, Vrecl, Milka, Frangež, Robert, "Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex" in Histochemistry and Cell Biology, 150, no. 1 (2018):93-102,
https://doi.org/10.1007/s00418-018-1670-0 . .

TY  - JOUR
AU  - Nikolić, Violeta N.
AU  - Spasojević, Vojislav
AU  - Panjan, Matjaž
AU  - Kopanja, Lazar
AU  - Mraković, Ana Đ.
AU  - Tadić, Marin
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1559
AB  - Several Fe2O3/SiO2 nanostructures were synthesized by the combination of the microemulsion and a sol-gel methods. Based on X-ray powder diffraction (XRD) and magnetic measurements (giant coercivity similar to 2.13 T) we identified epsilon-Fe2O3 (hard magnet) as the dominant crystalline phase. TEM analysis showed a wide size distribution of iron oxide nanoparticles (from 4 to 50 nm) with various morphologies (spherical, ellipsoidal and rod-like). We quantitatively described (computational analysis, MATLAB code) morphological properties of nanoparticles using the ellipticity of the shapes. The as-synthesized hard magnetic material was subjected to a post-annealing treatment at different temperatures (200, 500, 750, 1000 and 1100 degrees C) in order to investigate stability, formation and transformation of the epsilon-Fe2O3 polymorph. We found decreasing coercivity in the thermally treated samples up to the temperature of 750 degrees C (H-c=1245 Oe), followed by an observation of a surprising jump in coercivity H-c similar to 1.5 T after post-annealing at 1000 degrees C. We conclude that the re-formation of the epsilon-Fe2O3 structure during post-annealing at 1000 degrees C is the origin of the observed phenomena. The phase transformation epsilon-Fe2O3 - GT alpha-Fe2O3 and crystallization of amorphous silica in quartz and cristobalite were observed in the sample treated at 1100 degrees C.
T2  - Ceramics International
T1  - Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties
VL  - 43
IS  - 10
SP  - 7497
EP  - 7507
DO  - 10.1016/j.ceramint.2017.03.030
ER  - 

@article{
author = "Nikolić, Violeta N. and Spasojević, Vojislav and Panjan, Matjaž and Kopanja, Lazar and Mraković, Ana Đ. and Tadić, Marin",
year = "2017",
abstract = "Several Fe2O3/SiO2 nanostructures were synthesized by the combination of the microemulsion and a sol-gel methods. Based on X-ray powder diffraction (XRD) and magnetic measurements (giant coercivity similar to 2.13 T) we identified epsilon-Fe2O3 (hard magnet) as the dominant crystalline phase. TEM analysis showed a wide size distribution of iron oxide nanoparticles (from 4 to 50 nm) with various morphologies (spherical, ellipsoidal and rod-like). We quantitatively described (computational analysis, MATLAB code) morphological properties of nanoparticles using the ellipticity of the shapes. The as-synthesized hard magnetic material was subjected to a post-annealing treatment at different temperatures (200, 500, 750, 1000 and 1100 degrees C) in order to investigate stability, formation and transformation of the epsilon-Fe2O3 polymorph. We found decreasing coercivity in the thermally treated samples up to the temperature of 750 degrees C (H-c=1245 Oe), followed by an observation of a surprising jump in coercivity H-c similar to 1.5 T after post-annealing at 1000 degrees C. We conclude that the re-formation of the epsilon-Fe2O3 structure during post-annealing at 1000 degrees C is the origin of the observed phenomena. The phase transformation epsilon-Fe2O3 - GT alpha-Fe2O3 and crystallization of amorphous silica in quartz and cristobalite were observed in the sample treated at 1100 degrees C.",
journal = "Ceramics International",
title = "Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties",
volume = "43",
number = "10",
pages = "7497-7507",
doi = "10.1016/j.ceramint.2017.03.030"
}

Nikolić, V. N., Spasojević, V., Panjan, M., Kopanja, L., Mraković, A. Đ.,& Tadić, M.. (2017). Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties. in Ceramics International, 43(10), 7497-7507.
https://doi.org/10.1016/j.ceramint.2017.03.030

Nikolić VN, Spasojević V, Panjan M, Kopanja L, Mraković AĐ, Tadić M. Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties. in Ceramics International. 2017;43(10):7497-7507.
doi:10.1016/j.ceramint.2017.03.030 .

Nikolić, Violeta N., Spasojević, Vojislav, Panjan, Matjaž, Kopanja, Lazar, Mraković, Ana Đ., Tadić, Marin, "Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties" in Ceramics International, 43, no. 10 (2017):7497-7507,
https://doi.org/10.1016/j.ceramint.2017.03.030 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Milošević, Irena
AU  - Kralj, Slavko
AU  - Mitrić, Miodrag
AU  - Makovec, Darko
AU  - Saboungi, Marie-Louise
AU  - Motte, Laurence
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1662
AB  - We present a simple preparation route to obtain a nanoscale meta-stable hard-magnetic epsilon-Fe2O3 phase, using silica coated beta-FeOOH nanorods as a precursor and an annealing process. The synthesized epsilon-Fe2O3 nanoparticles exhibit large coercivity (H-C similar to 20 kOe at 300 K and H-C similar to 1.6 kOe at 400 K), confirming their high potential for practical applications.
T2  - Nanoscale
T1  - Synthesis of metastable hard-magnetic epsilon-Fe2O3 nanoparticles from silica-coated akaganeite nanorods
VL  - 9
IS  - 30
SP  - 10579
EP  - 10584
DO  - 10.1039/c7nr03639f
ER  - 

@article{
author = "Tadić, Marin and Milošević, Irena and Kralj, Slavko and Mitrić, Miodrag and Makovec, Darko and Saboungi, Marie-Louise and Motte, Laurence",
year = "2017",
abstract = "We present a simple preparation route to obtain a nanoscale meta-stable hard-magnetic epsilon-Fe2O3 phase, using silica coated beta-FeOOH nanorods as a precursor and an annealing process. The synthesized epsilon-Fe2O3 nanoparticles exhibit large coercivity (H-C similar to 20 kOe at 300 K and H-C similar to 1.6 kOe at 400 K), confirming their high potential for practical applications.",
journal = "Nanoscale",
title = "Synthesis of metastable hard-magnetic epsilon-Fe2O3 nanoparticles from silica-coated akaganeite nanorods",
volume = "9",
number = "30",
pages = "10579-10584",
doi = "10.1039/c7nr03639f"
}

Tadić, M., Milošević, I., Kralj, S., Mitrić, M., Makovec, D., Saboungi, M.,& Motte, L.. (2017). Synthesis of metastable hard-magnetic epsilon-Fe2O3 nanoparticles from silica-coated akaganeite nanorods. in Nanoscale, 9(30), 10579-10584.
https://doi.org/10.1039/c7nr03639f

Tadić M, Milošević I, Kralj S, Mitrić M, Makovec D, Saboungi M, Motte L. Synthesis of metastable hard-magnetic epsilon-Fe2O3 nanoparticles from silica-coated akaganeite nanorods. in Nanoscale. 2017;9(30):10579-10584.
doi:10.1039/c7nr03639f .

Tadić, Marin, Milošević, Irena, Kralj, Slavko, Mitrić, Miodrag, Makovec, Darko, Saboungi, Marie-Louise, Motte, Laurence, "Synthesis of metastable hard-magnetic epsilon-Fe2O3 nanoparticles from silica-coated akaganeite nanorods" in Nanoscale, 9, no. 30 (2017):10579-10584,
https://doi.org/10.1039/c7nr03639f . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Kopanja, Lazar
AU  - Panjan, Matjaž
AU  - Kralj, Slavko
AU  - Nikodinović-Runić, Jasmina
AU  - Stojanović, Zoran S.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1449
AB  - Hematite core-shell nanoparticles with plate-like morphology were synthesized using a one-step hydrothermal synthesis. An XRPD analysis indicates that the sample consist of single-phase alpha-Fe2O3 nanoparticles. SEM and TEM measurements show that the hematite sample is composed of uniform core-shell nanoplates with 10-20 nm thickness, 80-100 nm landscape dimensions (aspect ratio 5) and 3-4 nm thickness of the surface shells. We used computational methods for the quantitative analysis of the core-shell particle structure and circularity shape descriptor for the quantitative shape analysis of the nanoparticles from TEM micrographs. The calculated results indicated that a percentage of the shell area in the nanoparticle area (share [%]) is significant. The determined values of circularity in the perpendicular and oblique perspective clearly show shape anisotropy of the nanoplates. The magnetic properties revealed the ferromagnetic-like properties at room temperature with high coercivity H-C = 2340 Oe, pointing to the shape and surface effects. These results signify core-shell hematite nanoparticles for practical applications in magnetic devices. The synthesized hematite plate-like nanoparticles exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating the safe use of these nanoparticles for biomedical applications. (C) 2017 Elsevier B.V. All rights reserved.
T2  - Applied Surface Science
T1  - Synthesis of core-shell hematite (alpha-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity
VL  - 403
SP  - 628
EP  - 634
DO  - 10.1016/j.apsusc.2017.01.115
ER  - 

@article{
author = "Tadić, Marin and Kopanja, Lazar and Panjan, Matjaž and Kralj, Slavko and Nikodinović-Runić, Jasmina and Stojanović, Zoran S.",
year = "2017",
abstract = "Hematite core-shell nanoparticles with plate-like morphology were synthesized using a one-step hydrothermal synthesis. An XRPD analysis indicates that the sample consist of single-phase alpha-Fe2O3 nanoparticles. SEM and TEM measurements show that the hematite sample is composed of uniform core-shell nanoplates with 10-20 nm thickness, 80-100 nm landscape dimensions (aspect ratio 5) and 3-4 nm thickness of the surface shells. We used computational methods for the quantitative analysis of the core-shell particle structure and circularity shape descriptor for the quantitative shape analysis of the nanoparticles from TEM micrographs. The calculated results indicated that a percentage of the shell area in the nanoparticle area (share [%]) is significant. The determined values of circularity in the perpendicular and oblique perspective clearly show shape anisotropy of the nanoplates. The magnetic properties revealed the ferromagnetic-like properties at room temperature with high coercivity H-C = 2340 Oe, pointing to the shape and surface effects. These results signify core-shell hematite nanoparticles for practical applications in magnetic devices. The synthesized hematite plate-like nanoparticles exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating the safe use of these nanoparticles for biomedical applications. (C) 2017 Elsevier B.V. All rights reserved.",
journal = "Applied Surface Science",
title = "Synthesis of core-shell hematite (alpha-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity",
volume = "403",
pages = "628-634",
doi = "10.1016/j.apsusc.2017.01.115"
}

Tadić, M., Kopanja, L., Panjan, M., Kralj, S., Nikodinović-Runić, J.,& Stojanović, Z. S.. (2017). Synthesis of core-shell hematite (alpha-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity. in Applied Surface Science, 403, 628-634.
https://doi.org/10.1016/j.apsusc.2017.01.115

Tadić M, Kopanja L, Panjan M, Kralj S, Nikodinović-Runić J, Stojanović ZS. Synthesis of core-shell hematite (alpha-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity. in Applied Surface Science. 2017;403:628-634.
doi:10.1016/j.apsusc.2017.01.115 .

Tadić, Marin, Kopanja, Lazar, Panjan, Matjaž, Kralj, Slavko, Nikodinović-Runić, Jasmina, Stojanović, Zoran S., "Synthesis of core-shell hematite (alpha-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity" in Applied Surface Science, 403 (2017):628-634,
https://doi.org/10.1016/j.apsusc.2017.01.115 . .

TY  - JOUR
AU  - Nikolić, Violeta N.
AU  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Kopanja, Lazar
AU  - Cvjetićanin, Nikola
AU  - Spasojević, Vojislav
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1400
AB  - Magnetic properties of Fe2O3/SiO2 samples were studied after being produced by sol-gel synthesis and formation of epsilon-Fe2O3 polymorph. Samples were thermally treated, using different annealing temperatures and annealing times. The size and morphological characteristics of the iron oxide nanoparticles were examined using a TEM microscope. We used the ellipticity of shapes, which is a measure of how much the shape of a nanoparticle differs from a perfect ellipse, in order to quantitatively describe morphological properties of nanoparticles. Coercivity measurements were used to identify and monitor the formation of the epsilon-iron oxide phase during the thermal treatments (annealing). Coercivity values were in the range from 1.2 to 15.4 kOe, which is in accordance with previous experience regarding the existence of epsilon-Fe2O3. We have determined the optimal formation conditions for the epsilon-Fe2O3 polymorph (t=1050 degrees C for 7 h, H-c=15.4 kOe), as well as the narrow temperature interval (1050-1060 C) in which the polymorph abruptly vanished (H-c=2300 Oe), on the basis of results of the magnetic properties. The threshold temperature for the epsilon-Fe2O3 phase transformation was measured as 1060 degrees C. We found that different annealing temperatures and annealing times significantly affected magnetic properties of the examined samples.
T2  - Ceramics International
T1  - Influence of annealing treatment on magnetic properties of Fe2O3/SiO2 and formation of epsilon-Fe2O3 phase
VL  - 43
IS  - 3
SP  - 3147
EP  - 3155
DO  - 10.1016/j.ceramint.2016.11.132
ER  - 

@article{
author = "Nikolić, Violeta N. and Tadić, Marin and Panjan, Matjaž and Kopanja, Lazar and Cvjetićanin, Nikola and Spasojević, Vojislav",
year = "2017",
abstract = "Magnetic properties of Fe2O3/SiO2 samples were studied after being produced by sol-gel synthesis and formation of epsilon-Fe2O3 polymorph. Samples were thermally treated, using different annealing temperatures and annealing times. The size and morphological characteristics of the iron oxide nanoparticles were examined using a TEM microscope. We used the ellipticity of shapes, which is a measure of how much the shape of a nanoparticle differs from a perfect ellipse, in order to quantitatively describe morphological properties of nanoparticles. Coercivity measurements were used to identify and monitor the formation of the epsilon-iron oxide phase during the thermal treatments (annealing). Coercivity values were in the range from 1.2 to 15.4 kOe, which is in accordance with previous experience regarding the existence of epsilon-Fe2O3. We have determined the optimal formation conditions for the epsilon-Fe2O3 polymorph (t=1050 degrees C for 7 h, H-c=15.4 kOe), as well as the narrow temperature interval (1050-1060 C) in which the polymorph abruptly vanished (H-c=2300 Oe), on the basis of results of the magnetic properties. The threshold temperature for the epsilon-Fe2O3 phase transformation was measured as 1060 degrees C. We found that different annealing temperatures and annealing times significantly affected magnetic properties of the examined samples.",
journal = "Ceramics International",
title = "Influence of annealing treatment on magnetic properties of Fe2O3/SiO2 and formation of epsilon-Fe2O3 phase",
volume = "43",
number = "3",
pages = "3147-3155",
doi = "10.1016/j.ceramint.2016.11.132"
}

Nikolić, V. N., Tadić, M., Panjan, M., Kopanja, L., Cvjetićanin, N.,& Spasojević, V.. (2017). Influence of annealing treatment on magnetic properties of Fe2O3/SiO2 and formation of epsilon-Fe2O3 phase. in Ceramics International, 43(3), 3147-3155.
https://doi.org/10.1016/j.ceramint.2016.11.132

Nikolić VN, Tadić M, Panjan M, Kopanja L, Cvjetićanin N, Spasojević V. Influence of annealing treatment on magnetic properties of Fe2O3/SiO2 and formation of epsilon-Fe2O3 phase. in Ceramics International. 2017;43(3):3147-3155.
doi:10.1016/j.ceramint.2016.11.132 .

Nikolić, Violeta N., Tadić, Marin, Panjan, Matjaž, Kopanja, Lazar, Cvjetićanin, Nikola, Spasojević, Vojislav, "Influence of annealing treatment on magnetic properties of Fe2O3/SiO2 and formation of epsilon-Fe2O3 phase" in Ceramics International, 43, no. 3 (2017):3147-3155,
https://doi.org/10.1016/j.ceramint.2016.11.132 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Kralj, Slavko
AU  - Žunić, Dragiša
AU  - Lončar, Boris B.
AU  - Tadić, Marin
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1089
AB  - For the first time, particle shape analysis of silica coated iron oxide (maghemite/magnetite) nanoparticle clusters (core-shell nanostructures) is discussed using computational methods. We analyzed three samples of core-shell nanostructures synthesized with different thickness of the silica shell. A new computational method is presented and successfully applied to the segmentation of the core-shell nanoparticles, as one of the main problems in image analysis of the TEM micrographs. We have introduced the circularity coefficient, marked with k(circ) and defined as the ratio of circularity measure C-2(S) of nanoparticles core and circularity measure core-shell nanoparticles in order to answer the question how the shell affects the overall shape of the final core-shell structure, with respect to circularity. More precisely, the circularity coefficient determines whether the circularity of the core-shell nanoparticle is higher, lower or equal to the circularity of the core. We have also determined the shells share in the overall area of the core-shell nanoparticle. The core-shell nanoparticle clusters here investigated exhibit superparamagnetic properties at room temperature, thus emphasizing their potential for use in practical applications such as in biomedical and particle separation. We show that the saturation magnetization strength can be easily adjusted by controlling the thickness of the silica shell. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
PB  - Elsevier
T2  - Ceramics International
T1  - Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis
VL  - 42
IS  - 9
SP  - 10976
EP  - 10984
DO  - 10.1016/j.ceramint.2016.03.235
ER  - 

@article{
author = "Kopanja, Lazar and Kralj, Slavko and Žunić, Dragiša and Lončar, Boris B. and Tadić, Marin",
year = "2016",
abstract = "For the first time, particle shape analysis of silica coated iron oxide (maghemite/magnetite) nanoparticle clusters (core-shell nanostructures) is discussed using computational methods. We analyzed three samples of core-shell nanostructures synthesized with different thickness of the silica shell. A new computational method is presented and successfully applied to the segmentation of the core-shell nanoparticles, as one of the main problems in image analysis of the TEM micrographs. We have introduced the circularity coefficient, marked with k(circ) and defined as the ratio of circularity measure C-2(S) of nanoparticles core and circularity measure core-shell nanoparticles in order to answer the question how the shell affects the overall shape of the final core-shell structure, with respect to circularity. More precisely, the circularity coefficient determines whether the circularity of the core-shell nanoparticle is higher, lower or equal to the circularity of the core. We have also determined the shells share in the overall area of the core-shell nanoparticle. The core-shell nanoparticle clusters here investigated exhibit superparamagnetic properties at room temperature, thus emphasizing their potential for use in practical applications such as in biomedical and particle separation. We show that the saturation magnetization strength can be easily adjusted by controlling the thickness of the silica shell. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis",
volume = "42",
number = "9",
pages = "10976-10984",
doi = "10.1016/j.ceramint.2016.03.235"
}

Kopanja, L., Kralj, S., Žunić, D., Lončar, B. B.,& Tadić, M.. (2016). Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis. in Ceramics International
Elsevier., 42(9), 10976-10984.
https://doi.org/10.1016/j.ceramint.2016.03.235

Kopanja L, Kralj S, Žunić D, Lončar BB, Tadić M. Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis. in Ceramics International. 2016;42(9):10976-10984.
doi:10.1016/j.ceramint.2016.03.235 .

Kopanja, Lazar, Kralj, Slavko, Žunić, Dragiša, Lončar, Boris B., Tadić, Marin, "Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis" in Ceramics International, 42, no. 9 (2016):10976-10984,
https://doi.org/10.1016/j.ceramint.2016.03.235 . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Marković, Dragana
AU  - Panjan, Matjaž
AU  - Spasojević, Vojislav
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1317
AB  - We present a modified solution combustion synthesis method and measured magnetic properties of CaMnO3-delta (calcium manganite). The structure, morphology and magnetic properties of CaMnO3-delta were investigated by XRPD (X-ray powder diffraction), TEM (transmission electron microscopy), HRTEM (high-resolution transmission electron microscopy) and SQUID (superconducting quantum interference device). The XRPD study revealed that the prepared sample is composed of pure calcium manganite phase. The TEM and HRTEM images showed well-crystallized particles with a rough surface and particle size of about 100 nm. Magnetization measurements revealed magnetic transition at T-N=120 K, which corresponds to the Neel temperature of calcium manganite. Paramagnetic behavior was measured above the TN temperature. High irreversibility between the ZFC (zero-field cooled) and the FC (field cooled) curves below TN were observed. In addition, the separation between ZFC and FC curves increased with increasing magnetic field. We also show that the temperature values at the maxima of the ZFC curves are insensitive to the value of the applied DC magnetic field and to the frequency of the AC magnetic field. Magnetic measurements also indicate the presence of a strong antiferromagnetic exchange coupling with a Curie-Weiss temperature theta=-436 K. Magnetic moment of 4.33 mu(B) per Mn ion is determined from the Curie constant. This value of the magnetic moment suggests that Mn3+ and Mn4+ ions exist in the sample. Measurements of the magnetic hysteresis properties indicate a contribution of a ferromagnetic-like component in the sample. This is revealed by large coercivity and high remanence magnetization below TN. In this work we also studied field-cooled (up to 5 T) hysteresis properties of the sample. The detailed analysis of these results suggests a minor hysteresis loop behavior and no exchange bias.
T2  - Ceramics International
T1  - Solution combustion synthesis method and magnetic properties of synthesized polycrystalline calcium manganite CaMnO3-delta powder
VL  - 42
IS  - 16
SP  - 19365
EP  - 19371
DO  - 10.1016/j.ceramint.2016.09.109
ER  - 

@article{
author = "Tadić, Marin and Marković, Dragana and Panjan, Matjaž and Spasojević, Vojislav",
year = "2016",
abstract = "We present a modified solution combustion synthesis method and measured magnetic properties of CaMnO3-delta (calcium manganite). The structure, morphology and magnetic properties of CaMnO3-delta were investigated by XRPD (X-ray powder diffraction), TEM (transmission electron microscopy), HRTEM (high-resolution transmission electron microscopy) and SQUID (superconducting quantum interference device). The XRPD study revealed that the prepared sample is composed of pure calcium manganite phase. The TEM and HRTEM images showed well-crystallized particles with a rough surface and particle size of about 100 nm. Magnetization measurements revealed magnetic transition at T-N=120 K, which corresponds to the Neel temperature of calcium manganite. Paramagnetic behavior was measured above the TN temperature. High irreversibility between the ZFC (zero-field cooled) and the FC (field cooled) curves below TN were observed. In addition, the separation between ZFC and FC curves increased with increasing magnetic field. We also show that the temperature values at the maxima of the ZFC curves are insensitive to the value of the applied DC magnetic field and to the frequency of the AC magnetic field. Magnetic measurements also indicate the presence of a strong antiferromagnetic exchange coupling with a Curie-Weiss temperature theta=-436 K. Magnetic moment of 4.33 mu(B) per Mn ion is determined from the Curie constant. This value of the magnetic moment suggests that Mn3+ and Mn4+ ions exist in the sample. Measurements of the magnetic hysteresis properties indicate a contribution of a ferromagnetic-like component in the sample. This is revealed by large coercivity and high remanence magnetization below TN. In this work we also studied field-cooled (up to 5 T) hysteresis properties of the sample. The detailed analysis of these results suggests a minor hysteresis loop behavior and no exchange bias.",
journal = "Ceramics International",
title = "Solution combustion synthesis method and magnetic properties of synthesized polycrystalline calcium manganite CaMnO3-delta powder",
volume = "42",
number = "16",
pages = "19365-19371",
doi = "10.1016/j.ceramint.2016.09.109"
}

Tadić, M., Marković, D., Panjan, M.,& Spasojević, V.. (2016). Solution combustion synthesis method and magnetic properties of synthesized polycrystalline calcium manganite CaMnO3-delta powder. in Ceramics International, 42(16), 19365-19371.
https://doi.org/10.1016/j.ceramint.2016.09.109

Tadić M, Marković D, Panjan M, Spasojević V. Solution combustion synthesis method and magnetic properties of synthesized polycrystalline calcium manganite CaMnO3-delta powder. in Ceramics International. 2016;42(16):19365-19371.
doi:10.1016/j.ceramint.2016.09.109 .

Tadić, Marin, Marković, Dragana, Panjan, Matjaž, Spasojević, Vojislav, "Solution combustion synthesis method and magnetic properties of synthesized polycrystalline calcium manganite CaMnO3-delta powder" in Ceramics International, 42, no. 16 (2016):19365-19371,
https://doi.org/10.1016/j.ceramint.2016.09.109 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Milošević, Irena
AU  - Panjan, Matjaž
AU  - Damnjanović, Vesna
AU  - Tadić, Marin
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/901
AB  - We report the synthesis and magnetic properties of hematite/amorphous silica nanostructures. Raman spectroscopy showed the formation of a hematite phase. A transmission electron microscopy (TEM) revealed spherically shaped hematite nanoparticles, well-dispersed in an amorphous silica matrix. In order to quantitatively describe morphological properties of nanoparticles, we use the circularity of shapes as a measure of how circular a shape is. Diameters of about 5 nm and a narrow size distribution of nanoparticles are observed. The obtained hematite nanoparticles exhibit superparamagnetic properties at room temperature (SPION). The sample does not display the Morin transition. The FC hysteresis loop at 5 K has shown an exchange bias effect. These results have been compared to those previously reported for alpha-Fe2O3/SiO2 nanosystems in the literature. These comparisons reveal that the sol-gel combustion method yields hematite nanoparticles with a higher magnetization and magnetic moment. These data indicate the existence of an additional factor that contributes to magnetization. We suggest that the increased magnetization is due to an increased number of the surface spins caused by the breaking of large numbers of exchange bonds between surface atoms (disordered structure). This leads to an increase in the magnetic moment per a hematite nanoparticle and an exchange bias effect. We have concluded that the combustion-related part of this synthesis method enhances surface effects, i.e. it promotes the breaking of bonds and surface disordered layers, which results in these magnetic properties. Such interesting structural and magnetic properties of hematite might be important in future practical applications and fundamental research. (C) 2015 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Applied Surface Science
T1  - Sol-gel combustion synthesis, particle shape analysis and magnetic properties of hematite (alpha-Fe2O3) nanoparticles embedded in an amorphous silica matrix
VL  - 362
SP  - 380
EP  - 386
DO  - 10.1016/j.apsusc.2015.11.238
ER  - 

@article{
author = "Kopanja, Lazar and Milošević, Irena and Panjan, Matjaž and Damnjanović, Vesna and Tadić, Marin",
year = "2016",
abstract = "We report the synthesis and magnetic properties of hematite/amorphous silica nanostructures. Raman spectroscopy showed the formation of a hematite phase. A transmission electron microscopy (TEM) revealed spherically shaped hematite nanoparticles, well-dispersed in an amorphous silica matrix. In order to quantitatively describe morphological properties of nanoparticles, we use the circularity of shapes as a measure of how circular a shape is. Diameters of about 5 nm and a narrow size distribution of nanoparticles are observed. The obtained hematite nanoparticles exhibit superparamagnetic properties at room temperature (SPION). The sample does not display the Morin transition. The FC hysteresis loop at 5 K has shown an exchange bias effect. These results have been compared to those previously reported for alpha-Fe2O3/SiO2 nanosystems in the literature. These comparisons reveal that the sol-gel combustion method yields hematite nanoparticles with a higher magnetization and magnetic moment. These data indicate the existence of an additional factor that contributes to magnetization. We suggest that the increased magnetization is due to an increased number of the surface spins caused by the breaking of large numbers of exchange bonds between surface atoms (disordered structure). This leads to an increase in the magnetic moment per a hematite nanoparticle and an exchange bias effect. We have concluded that the combustion-related part of this synthesis method enhances surface effects, i.e. it promotes the breaking of bonds and surface disordered layers, which results in these magnetic properties. Such interesting structural and magnetic properties of hematite might be important in future practical applications and fundamental research. (C) 2015 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Applied Surface Science",
title = "Sol-gel combustion synthesis, particle shape analysis and magnetic properties of hematite (alpha-Fe2O3) nanoparticles embedded in an amorphous silica matrix",
volume = "362",
pages = "380-386",
doi = "10.1016/j.apsusc.2015.11.238"
}

Kopanja, L., Milošević, I., Panjan, M., Damnjanović, V.,& Tadić, M.. (2016). Sol-gel combustion synthesis, particle shape analysis and magnetic properties of hematite (alpha-Fe2O3) nanoparticles embedded in an amorphous silica matrix. in Applied Surface Science
Elsevier., 362, 380-386.
https://doi.org/10.1016/j.apsusc.2015.11.238

Kopanja L, Milošević I, Panjan M, Damnjanović V, Tadić M. Sol-gel combustion synthesis, particle shape analysis and magnetic properties of hematite (alpha-Fe2O3) nanoparticles embedded in an amorphous silica matrix. in Applied Surface Science. 2016;362:380-386.
doi:10.1016/j.apsusc.2015.11.238 .

Kopanja, Lazar, Milošević, Irena, Panjan, Matjaž, Damnjanović, Vesna, Tadić, Marin, "Sol-gel combustion synthesis, particle shape analysis and magnetic properties of hematite (alpha-Fe2O3) nanoparticles embedded in an amorphous silica matrix" in Applied Surface Science, 362 (2016):380-386,
https://doi.org/10.1016/j.apsusc.2015.11.238 . .

TY  - JOUR
AU  - Ivetić, Tamara B.
AU  - Tadić, Marin
AU  - Jagodič, Marko
AU  - Gyergyek, Sašo
AU  - Štrbac, Goran R.
AU  - Lukić-Petrović, Svetlana R.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1316
AB  - This paper reports on novel cobalt oxide nanoparticles (NPs) embedded in an amorphous silica (SiO2) matrix, synthesized using a modified sol-gel method. SEM and TEM images show as-synthesized particles to aggregate in the shape of spheres and less than 5 nm in size, while XRD and SAED analysis both point to well crystallized cubic spinel cobalt oxide phase with an average crystallite size of about 4.6 nm. Raman analysis confirms the formation of cobalt (III) oxide (Co3O4) NPs. As-synthesized Co3O4 single-nanocrystallite has magnetic properties that correlate with finite size effects and uncompensated surface spins. Temperature dependence of ZFC-FC magnetization curves reveals a sharp peak around 10 K which corresponds to the blocking temperature. A Curie-Weiss behavior of magnetization above 25 K shows lower Neel temperature of the sample compared with its bulk counterpart T-N=40 K (possibly due to crystal defects and nano-dimensionality of the particles). The magnetic measurements exhibit high magnetization at low temperatures (M-s=54.3 emu/g) which can be associated with random canting of the particles surface spins and uncompensated spins in the core which tends to interact ferromagnetically at low temperatures. The initial magnetization curve falls out from the hysteresis loop at 5 K, which could be also the effect of surface spins. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
T2  - Ceramics International
T1  - Structure and magnetic properties of Co3O4/SiO2 nanocomposite synthesized using combustion assisted sol-gel method
VL  - 42
IS  - 16
SP  - 18312
EP  - 18317
DO  - 10.1016/j.ceramint.2016.08.159
ER  - 

@article{
author = "Ivetić, Tamara B. and Tadić, Marin and Jagodič, Marko and Gyergyek, Sašo and Štrbac, Goran R. and Lukić-Petrović, Svetlana R.",
year = "2016",
abstract = "This paper reports on novel cobalt oxide nanoparticles (NPs) embedded in an amorphous silica (SiO2) matrix, synthesized using a modified sol-gel method. SEM and TEM images show as-synthesized particles to aggregate in the shape of spheres and less than 5 nm in size, while XRD and SAED analysis both point to well crystallized cubic spinel cobalt oxide phase with an average crystallite size of about 4.6 nm. Raman analysis confirms the formation of cobalt (III) oxide (Co3O4) NPs. As-synthesized Co3O4 single-nanocrystallite has magnetic properties that correlate with finite size effects and uncompensated surface spins. Temperature dependence of ZFC-FC magnetization curves reveals a sharp peak around 10 K which corresponds to the blocking temperature. A Curie-Weiss behavior of magnetization above 25 K shows lower Neel temperature of the sample compared with its bulk counterpart T-N=40 K (possibly due to crystal defects and nano-dimensionality of the particles). The magnetic measurements exhibit high magnetization at low temperatures (M-s=54.3 emu/g) which can be associated with random canting of the particles surface spins and uncompensated spins in the core which tends to interact ferromagnetically at low temperatures. The initial magnetization curve falls out from the hysteresis loop at 5 K, which could be also the effect of surface spins. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.",
journal = "Ceramics International",
title = "Structure and magnetic properties of Co3O4/SiO2 nanocomposite synthesized using combustion assisted sol-gel method",
volume = "42",
number = "16",
pages = "18312-18317",
doi = "10.1016/j.ceramint.2016.08.159"
}

Ivetić, T. B., Tadić, M., Jagodič, M., Gyergyek, S., Štrbac, G. R.,& Lukić-Petrović, S. R.. (2016). Structure and magnetic properties of Co3O4/SiO2 nanocomposite synthesized using combustion assisted sol-gel method. in Ceramics International, 42(16), 18312-18317.
https://doi.org/10.1016/j.ceramint.2016.08.159

Ivetić TB, Tadić M, Jagodič M, Gyergyek S, Štrbac GR, Lukić-Petrović SR. Structure and magnetic properties of Co3O4/SiO2 nanocomposite synthesized using combustion assisted sol-gel method. in Ceramics International. 2016;42(16):18312-18317.
doi:10.1016/j.ceramint.2016.08.159 .

Ivetić, Tamara B., Tadić, Marin, Jagodič, Marko, Gyergyek, Sašo, Štrbac, Goran R., Lukić-Petrović, Svetlana R., "Structure and magnetic properties of Co3O4/SiO2 nanocomposite synthesized using combustion assisted sol-gel method" in Ceramics International, 42, no. 16 (2016):18312-18317,
https://doi.org/10.1016/j.ceramint.2016.08.159 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Žunić, Dragiša
AU  - Lončar, Boris B.
AU  - Gyergyek, Sašo
AU  - Tadić, Marin
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1198
AB  - We propose using a new circularity measure, and an ellipticity measure. Observing an example of hematite (alpha-Fe2O3) nanoparticles, we compared and discussed a new circularity measure, with a standard measure. It has been shown that using the new measure gives better results when working with low-quality images or with low-resolution images. Using the same images modified ellipticity measure has also been discussed. We have analyzed the problems arising from computing the elongation of a shape. We have shown that the standard approach to compute elongation is not appropriate for some particles. We presented the application of the modified approach to solve this problem. (C) 2016 Elsevier Ltd. All rights reserved.
T2  - Measurement
T1  - Quantifying shapes of nanoparticles using modified circularity and ellipticity measures
VL  - 92
SP  - 252
EP  - 263
DO  - 10.1016/j.measurement.2016.06.021
ER  - 

@article{
author = "Kopanja, Lazar and Žunić, Dragiša and Lončar, Boris B. and Gyergyek, Sašo and Tadić, Marin",
year = "2016",
abstract = "We propose using a new circularity measure, and an ellipticity measure. Observing an example of hematite (alpha-Fe2O3) nanoparticles, we compared and discussed a new circularity measure, with a standard measure. It has been shown that using the new measure gives better results when working with low-quality images or with low-resolution images. Using the same images modified ellipticity measure has also been discussed. We have analyzed the problems arising from computing the elongation of a shape. We have shown that the standard approach to compute elongation is not appropriate for some particles. We presented the application of the modified approach to solve this problem. (C) 2016 Elsevier Ltd. All rights reserved.",
journal = "Measurement",
title = "Quantifying shapes of nanoparticles using modified circularity and ellipticity measures",
volume = "92",
pages = "252-263",
doi = "10.1016/j.measurement.2016.06.021"
}

Kopanja, L., Žunić, D., Lončar, B. B., Gyergyek, S.,& Tadić, M.. (2016). Quantifying shapes of nanoparticles using modified circularity and ellipticity measures. in Measurement, 92, 252-263.
https://doi.org/10.1016/j.measurement.2016.06.021

Kopanja L, Žunić D, Lončar BB, Gyergyek S, Tadić M. Quantifying shapes of nanoparticles using modified circularity and ellipticity measures. in Measurement. 2016;92:252-263.
doi:10.1016/j.measurement.2016.06.021 .

Kopanja, Lazar, Žunić, Dragiša, Lončar, Boris B., Gyergyek, Sašo, Tadić, Marin, "Quantifying shapes of nanoparticles using modified circularity and ellipticity measures" in Measurement, 92 (2016):252-263,
https://doi.org/10.1016/j.measurement.2016.06.021 . .

TY  - CONF
AU  - Savić, Slavica
AU  - Tadić, Marin
AU  - Jagličić, Zvonko
AU  - Mančić, Lidija
AU  - Vojisavljević, Katarina
AU  - Branković, Goran O.
PY  - 2015
UR  - http://dais.sanu.ac.rs/123456789/742
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7524
AB  - Spinel materials based on Mn and Ni has been intensively studied over the past years due to their excellent semiconductor properties. Nickel manganite as NTC thermistor is widely used today in different industrial sectors. Here we report the complex polymerization method (CPM) for producing nickel manganite fine particles with a homogeneous distribution of constituent cations in the crystal lattice that ensures formation of dense monophased ceramic with the novel magnetic properties after been sintered in oxygen and air atmosphere. Phase composition of the synthesized materials was examined by XRPD, while the morphology of the powder and microstructure of ceramic were investigated using FESEM and SEM analyses, respectively. The magnetic properties of the samples have been studied by measuring the temperature and field dependence of magnetization. Magnetic measurements of M(T) reveal rather complex magnetic properties and multiple magnetic phase transitions. In the case of air atmosphere we found three magnetic phase transitions with transition temperatures at TM1=35 K, TM2=101 K and TM3=120 K. TM1 maximum is strongly dependent on the strength of the applied magnetic field (TM1 decreases with increasing applied field) whereas the TM3 is field independent The values of the coercivity, remanent magnetization and saturation magnetization at 100 K are: HC = 184 Oe, Mr = 1.92 emu/g and MS = 7.88 emu/g, respectively. The measured values at 5 K are HC = 1035 Oe, Mr = 7.70 emu/g and MS = 14.47 emu/g. Moreover, hysteresis properties measured after cooling of the sample in magnetic field show exchange bias effect with an exchange bias field |HEB=196 Oe. For the sample synthetized in oxygen atmosphere, the magnetization dependence of temperature M(T) and AC susceptibility data obtained from SQUID measurements clearly demonstrates that quadruple magnetic phase transitions can be readily detected at TM1~115 K, TM2~105 K, TM3~38 K and TM4~7 K. These findings suggest the novel magnetic transition for nickel manganite at low temperature TM4. The temperatures of observed maximums in χ’(T) and χ’’(T) parts of susceptibility are frequency independent, whereas the height of the peaks decreases with increasing frequency. The fact that TM4 does not shift with the increase of the frequency led us to the conclusion that there are no spin-glass/surface effect and/or blocking temperature/finite size effect connected to the NiMn2O4 ceramic. Therefore, the low-temperature peak TM4 in AC susceptibility is associated with ferromagnetic-like and antiferromagnetic-like magnetic transition in the interfacial FM/AFM internal structure. The exchange bias effect was found in a field cooled hysteresis loops at 5 K. The field cooling of the sample was under a magnetic field of 100 Oe and 10 kOe whereas the determined exchange bias fields were |HEB|=129 Oe and 182 Oe, respectively. The analysis of the results and comparison with literature data allowed us to conjecture that the mixed oxidation states of Mn ions and ferromagnetic and antiferromagnetic sublattice orders tailor these interesting magnetic properties.
PB  - Belgrade : Institute for Multidisciplinary Research
C3  - Programme and the Book of Abstracts / 3rd Conference of the Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbia
T1  - Magnetic properties of nickel manganite obtained by a complex polymerization method
SP  - 111
EP  - 112
UR  - https://hdl.handle.net/21.15107/rcub_vinar_7524
ER  - 

@conference{
author = "Savić, Slavica and Tadić, Marin and Jagličić, Zvonko and Mančić, Lidija and Vojisavljević, Katarina and Branković, Goran O.",
year = "2015",
abstract = "Spinel materials based on Mn and Ni has been intensively studied over the past years due to their excellent semiconductor properties. Nickel manganite as NTC thermistor is widely used today in different industrial sectors. Here we report the complex polymerization method (CPM) for producing nickel manganite fine particles with a homogeneous distribution of constituent cations in the crystal lattice that ensures formation of dense monophased ceramic with the novel magnetic properties after been sintered in oxygen and air atmosphere. Phase composition of the synthesized materials was examined by XRPD, while the morphology of the powder and microstructure of ceramic were investigated using FESEM and SEM analyses, respectively. The magnetic properties of the samples have been studied by measuring the temperature and field dependence of magnetization. Magnetic measurements of M(T) reveal rather complex magnetic properties and multiple magnetic phase transitions. In the case of air atmosphere we found three magnetic phase transitions with transition temperatures at TM1=35 K, TM2=101 K and TM3=120 K. TM1 maximum is strongly dependent on the strength of the applied magnetic field (TM1 decreases with increasing applied field) whereas the TM3 is field independent The values of the coercivity, remanent magnetization and saturation magnetization at 100 K are: HC = 184 Oe, Mr = 1.92 emu/g and MS = 7.88 emu/g, respectively. The measured values at 5 K are HC = 1035 Oe, Mr = 7.70 emu/g and MS = 14.47 emu/g. Moreover, hysteresis properties measured after cooling of the sample in magnetic field show exchange bias effect with an exchange bias field |HEB=196 Oe. For the sample synthetized in oxygen atmosphere, the magnetization dependence of temperature M(T) and AC susceptibility data obtained from SQUID measurements clearly demonstrates that quadruple magnetic phase transitions can be readily detected at TM1~115 K, TM2~105 K, TM3~38 K and TM4~7 K. These findings suggest the novel magnetic transition for nickel manganite at low temperature TM4. The temperatures of observed maximums in χ’(T) and χ’’(T) parts of susceptibility are frequency independent, whereas the height of the peaks decreases with increasing frequency. The fact that TM4 does not shift with the increase of the frequency led us to the conclusion that there are no spin-glass/surface effect and/or blocking temperature/finite size effect connected to the NiMn2O4 ceramic. Therefore, the low-temperature peak TM4 in AC susceptibility is associated with ferromagnetic-like and antiferromagnetic-like magnetic transition in the interfacial FM/AFM internal structure. The exchange bias effect was found in a field cooled hysteresis loops at 5 K. The field cooling of the sample was under a magnetic field of 100 Oe and 10 kOe whereas the determined exchange bias fields were |HEB|=129 Oe and 182 Oe, respectively. The analysis of the results and comparison with literature data allowed us to conjecture that the mixed oxidation states of Mn ions and ferromagnetic and antiferromagnetic sublattice orders tailor these interesting magnetic properties.",
publisher = "Belgrade : Institute for Multidisciplinary Research",
journal = "Programme and the Book of Abstracts / 3rd Conference of the Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbia",
title = "Magnetic properties of nickel manganite obtained by a complex polymerization method",
pages = "111-112",
url = "https://hdl.handle.net/21.15107/rcub_vinar_7524"
}

Savić, S., Tadić, M., Jagličić, Z., Mančić, L., Vojisavljević, K.,& Branković, G. O.. (2015). Magnetic properties of nickel manganite obtained by a complex polymerization method. in Programme and the Book of Abstracts / 3rd Conference of the Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbia
Belgrade : Institute for Multidisciplinary Research., 111-112.
https://hdl.handle.net/21.15107/rcub_vinar_7524

Savić S, Tadić M, Jagličić Z, Mančić L, Vojisavljević K, Branković GO. Magnetic properties of nickel manganite obtained by a complex polymerization method. in Programme and the Book of Abstracts / 3rd Conference of the Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbia. 2015;:111-112.
https://hdl.handle.net/21.15107/rcub_vinar_7524 .

Savić, Slavica, Tadić, Marin, Jagličić, Zvonko, Mančić, Lidija, Vojisavljević, Katarina, Branković, Goran O., "Magnetic properties of nickel manganite obtained by a complex polymerization method" in Programme and the Book of Abstracts / 3rd Conference of the Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbia (2015):111-112,
https://hdl.handle.net/21.15107/rcub_vinar_7524 .