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  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Jagodič, Marko
AU  - Hanžel, Darko
AU  - Makovec, Darko
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/59
AB  - The aim of this work is to present the magnetic properties of novel superparamagnetic-iNANOvative (TM)vertical bar silica nanoparticle clusters. A TEM analysis showed that these nanoparticle clusters, approximately 80 nm in size, contained an assembly of maghemite nanoparticles in the core and an amorphous silica shell. The maghemite nanoparticles in the core were approximately 10 nm in size, whereas the uniform silica shell was approximately 15-nm thick. The number of magnetic nanoparticles that were densely packed in the core of the single nanocluster was estimated to be approximately 67, resulting in a high magnetic moment for the single nanocluster of m(nc) similar to 1.2 x 10(6) mu(B). This magnetic property of the nanoparticle cluster is advantageous for its easy manipulation using an external magnetic field, for example, in biomedical applications, such as drug delivery, or for magnetic separation in biotechnology. The magnetic properties of the iNANOvative (TM)vertical bar silica nanoparticle clusters were systematically studied, with a special focus on the influence of the magnetic interactions between the nanoparticles in the core. For comparison, the nanoparticle clusters were annealed for 3 h at 300 degrees C in air. The annealing had no influence on the nanoparticles size and phase; however, it had a unique effect on the magnetic properties, i.e., a decrease of the blocking temperature and a weakening of the inter-particle interactions. We believe that this surprising observation is related to the thermal decomposition of the organic surfactant on the surfaces of the nanoparticles at the high annealing temperatures, which resulted in the formation of amorphous carbon inside the nanocluster. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Applied Surface Science
T1  - Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment
VL  - 322
SP  - 255
EP  - 264
DO  - 10.1016/j.apsusc.2014.09.181
ER  - 

@article{
author = "Tadić, Marin and Kralj, Slavko and Jagodič, Marko and Hanžel, Darko and Makovec, Darko",
year = "2014",
abstract = "The aim of this work is to present the magnetic properties of novel superparamagnetic-iNANOvative (TM)vertical bar silica nanoparticle clusters. A TEM analysis showed that these nanoparticle clusters, approximately 80 nm in size, contained an assembly of maghemite nanoparticles in the core and an amorphous silica shell. The maghemite nanoparticles in the core were approximately 10 nm in size, whereas the uniform silica shell was approximately 15-nm thick. The number of magnetic nanoparticles that were densely packed in the core of the single nanocluster was estimated to be approximately 67, resulting in a high magnetic moment for the single nanocluster of m(nc) similar to 1.2 x 10(6) mu(B). This magnetic property of the nanoparticle cluster is advantageous for its easy manipulation using an external magnetic field, for example, in biomedical applications, such as drug delivery, or for magnetic separation in biotechnology. The magnetic properties of the iNANOvative (TM)vertical bar silica nanoparticle clusters were systematically studied, with a special focus on the influence of the magnetic interactions between the nanoparticles in the core. For comparison, the nanoparticle clusters were annealed for 3 h at 300 degrees C in air. The annealing had no influence on the nanoparticles size and phase; however, it had a unique effect on the magnetic properties, i.e., a decrease of the blocking temperature and a weakening of the inter-particle interactions. We believe that this surprising observation is related to the thermal decomposition of the organic surfactant on the surfaces of the nanoparticles at the high annealing temperatures, which resulted in the formation of amorphous carbon inside the nanocluster. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Applied Surface Science",
title = "Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment",
volume = "322",
pages = "255-264",
doi = "10.1016/j.apsusc.2014.09.181"
}

Tadić, M., Kralj, S., Jagodič, M., Hanžel, D.,& Makovec, D.. (2014). Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment. in Applied Surface Science, 322, 255-264.
https://doi.org/10.1016/j.apsusc.2014.09.181

Tadić M, Kralj S, Jagodič M, Hanžel D, Makovec D. Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment. in Applied Surface Science. 2014;322:255-264.
doi:10.1016/j.apsusc.2014.09.181 .

Tadić, Marin, Kralj, Slavko, Jagodič, Marko, Hanžel, Darko, Makovec, Darko, "Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment" in Applied Surface Science, 322 (2014):255-264,
https://doi.org/10.1016/j.apsusc.2014.09.181 . .