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Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties
dc.creator | Nikolić, Violeta N. | |
dc.creator | Spasojević, Vojislav | |
dc.creator | Panjan, Matjaž | |
dc.creator | Kopanja, Lazar | |
dc.creator | Mraković, Ana Đ. | |
dc.creator | Tadić, Marin | |
dc.date.accessioned | 2018-03-01T17:36:16Z | |
dc.date.available | 2018-03-01T17:36:16Z | |
dc.date.issued | 2017 | |
dc.identifier.issn | 0272-8842 | |
dc.identifier.issn | 1873-3956 | |
dc.identifier.uri | https://vinar.vin.bg.ac.rs/handle/123456789/1559 | |
dc.description.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. | en |
dc.relation | info:eu-repo/grantAgreement/MESTD/Integrated and Interdisciplinary Research (IIR or III)/45015/RS// | |
dc.relation | Serbian-Slovenian bilateral project [BI-RS/16-17-030] | |
dc.rights | restrictedAccess | en |
dc.source | Ceramics International | en |
dc.subject | Sol-gel synthesis | en |
dc.subject | epsilon-Fe2O3 | en |
dc.subject | Magnetic properties | en |
dc.subject | Phase transformation | en |
dc.subject | Maghemite (gamma-Fe2O3) | en |
dc.subject | Hematite (alpha-Fe2O3) | en |
dc.title | Re-formation of metastable epsilon-Fe2O3 in post-annealing of Fe2O3/SiO2 nanostructure: Synthesis, computational particle shape analysis in micrographs and magnetic properties | en |
dc.type | article | en |
dc.rights.license | ARR | |
dcterms.abstract | Копања, Лазар; Николић Виолета; Пањан, Матјаз; Спасојевић Војислав; Мраковић Aна; Тадић Марин; | |
dc.citation.volume | 43 | |
dc.citation.issue | 10 | |
dc.citation.spage | 7497 | |
dc.citation.epage | 7507 | |
dc.identifier.wos | 000400880000017 | |
dc.identifier.doi | 10.1016/j.ceramint.2017.03.030 | |
dc.citation.rank | aM21 | |
dc.type.version | publishedVersion | |
dc.identifier.scopus | 2-s2.0-85014838558 |