TY  - JOUR
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Kopanja, Lazar
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5911
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
EP  - 133
SP  - 123
VL  - 148
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",
pages = "133-123",
volume = "148",
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  - Kopanja, Lazar
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Žunić, Joviša
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5877
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
EP  - 12351
IS  - 11
SP  - 12340
VL  - 44
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",
pages = "12351-12340",
number = "11",
volume = "44",
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  - Trpkov, Đorđe
AU  - Panjan, Matjaž
AU  - Kopanja, Lazar
AU  - Tadić, Marin
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5874
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
EP  - 438
SP  - 427
VL  - 457
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",
pages = "438-427",
volume = "457",
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  - JOUR
AU  - Tadić, Marin
AU  - Kopanja, Lazar
AU  - Panjan, Matjaž
AU  - Kralj, Slavko
AU  - Nikodinović Runić, Jasmina
AU  - Stojanović, Zoran S.
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5854
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 α-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 HC = 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.
T2  - Applied Surface Science
T1  - Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity
EP  - 634
SP  - 628
VL  - 403
DO  - 10.1016/j.apsusc.2017.01.115
UR  - https://hdl.handle.net/21.15107/rcub_dais_2349
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 α-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 HC = 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.",
journal = "Applied Surface Science",
title = "Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity",
pages = "634-628",
volume = "403",
doi = "10.1016/j.apsusc.2017.01.115",
url = "https://hdl.handle.net/21.15107/rcub_dais_2349"
}

Tadić, M., Kopanja, L., Panjan, M., Kralj, S., Nikodinović Runić, J.,& Stojanović, Z. S.. (2017). Synthesis of core-shell hematite (α-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
https://hdl.handle.net/21.15107/rcub_dais_2349

Tadić M, Kopanja L, Panjan M, Kralj S, Nikodinović Runić J, Stojanović ZS. Synthesis of core-shell hematite (α-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
https://hdl.handle.net/21.15107/rcub_dais_2349 .

Tadić, Marin, Kopanja, Lazar, Panjan, Matjaž, Kralj, Slavko, Nikodinović Runić, Jasmina, Stojanović, Zoran S., "Synthesis of core-shell hematite (α-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 .,
https://hdl.handle.net/21.15107/rcub_dais_2349 .

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  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5852
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
EP  - 7507
IS  - 10
SP  - 7497
VL  - 43
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",
pages = "7507-7497",
number = "10",
volume = "43",
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  - Nikolić, Violeta N.
AU  - Tadić, Marin
AU  - Panjan, Matjaž
AU  - Kopanja, Lazar
AU  - Cvjetićanin, Nikola
AU  - Spasojević, Vojislav
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5822
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
EP  - 3155
IS  - 3
SP  - 3147
VL  - 43
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",
pages = "3155-3147",
number = "3",
volume = "43",
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 . .