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 . .