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  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Damnjanović, Vesna
AU  - Milošević, Irena
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/225
AB  - Hematite (alpha-Fe2O3) nanoparticles are successfully synthesized by using the hydrothermal synthesis method. An X-ray powder diffraction (XRPD) of the sample shows formation of the nanocrystalline alpha-Fe2O3 phase. A transmission electron microscopy (TEM) measurements show spherical morphology of the hematite nanoparticles and narrow size distribution. An average hematite nanoparticle size is estimated to be about 8 nm by TEM and XRD. Magnetic properties were measured using a superconducting quantum interference device (SQUID) magnetometry. Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves below T-irr =103 K (irreversibility temperature). The ZFC magnetization curve showed maximum at T-B = 52 K (blocking temperature). The sample did not exhibit the Morin transition. The M(H) (magnetization versus magnetic field) dependence at 300 K showed properties of superparamagnetic iron oxide nanoparticles (SPION). The M(H) data were successfully fitted by the Langevin function and magnetic moment,up = 657 tu and diameter d= 8.1 nm were determined. Furthermore, magnetic measurements showed high magnetization at room temperature (M-S =3.98 emu/g), which is desirable for application in spintronics and biomedicine. Core-shell structure of the nanoparticles was used to describe high magnetization of the hematite nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Applied Surface Science
T1  - Magnetic properties of hematite (alpha-Fe2O3) nanoparticles prepared by hydrothermal synthesis method
VL  - 320
SP  - 183
EP  - 187
DO  - 10.1016/j.apsusc.2014.08.103
ER  - 

@article{
author = "Tadić, Marin and Panjan, Matjaž and Damnjanović, Vesna and Milošević, Irena",
year = "2014",
abstract = "Hematite (alpha-Fe2O3) nanoparticles are successfully synthesized by using the hydrothermal synthesis method. An X-ray powder diffraction (XRPD) of the sample shows formation of the nanocrystalline alpha-Fe2O3 phase. A transmission electron microscopy (TEM) measurements show spherical morphology of the hematite nanoparticles and narrow size distribution. An average hematite nanoparticle size is estimated to be about 8 nm by TEM and XRD. Magnetic properties were measured using a superconducting quantum interference device (SQUID) magnetometry. Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves below T-irr =103 K (irreversibility temperature). The ZFC magnetization curve showed maximum at T-B = 52 K (blocking temperature). The sample did not exhibit the Morin transition. The M(H) (magnetization versus magnetic field) dependence at 300 K showed properties of superparamagnetic iron oxide nanoparticles (SPION). The M(H) data were successfully fitted by the Langevin function and magnetic moment,up = 657 tu and diameter d= 8.1 nm were determined. Furthermore, magnetic measurements showed high magnetization at room temperature (M-S =3.98 emu/g), which is desirable for application in spintronics and biomedicine. Core-shell structure of the nanoparticles was used to describe high magnetization of the hematite nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Applied Surface Science",
title = "Magnetic properties of hematite (alpha-Fe2O3) nanoparticles prepared by hydrothermal synthesis method",
volume = "320",
pages = "183-187",
doi = "10.1016/j.apsusc.2014.08.103"
}

Tadić, M., Panjan, M., Damnjanović, V.,& Milošević, I.. (2014). Magnetic properties of hematite (alpha-Fe2O3) nanoparticles prepared by hydrothermal synthesis method. in Applied Surface Science, 320, 183-187.
https://doi.org/10.1016/j.apsusc.2014.08.103

Tadić M, Panjan M, Damnjanović V, Milošević I. Magnetic properties of hematite (alpha-Fe2O3) nanoparticles prepared by hydrothermal synthesis method. in Applied Surface Science. 2014;320:183-187.
doi:10.1016/j.apsusc.2014.08.103 .

Tadić, Marin, Panjan, Matjaž, Damnjanović, Vesna, Milošević, Irena, "Magnetic properties of hematite (alpha-Fe2O3) nanoparticles prepared by hydrothermal synthesis method" in Applied Surface Science, 320 (2014):183-187,
https://doi.org/10.1016/j.apsusc.2014.08.103 . .