Stabilization of the high coercivity ε-Fe.sub.2./sub.O.sub.3./sub. phase in the CeO.sub.2./sub.-Fe.sub.2./sub.O.sub.3./sub./SiO2.sub.2./sub. nanocomposites

0385566 - FZÚ 2013 RIV US eng J - Článek v odborném periodiku
Mantlíková, Alice - Poltierová Vejpravová, Jana - Bittová, Barbara - Burianová, Simona - Nižňanský, D. - Ardu, A. - Cannas, C.
Stabilization of the high coercivity ε-Fe₂O₃ phase in the CeO₂-Fe₂O₃/SiO2₂ nanocomposites.
Journal of Solid State Chemistry. Roč. 191, č. 7 (2012), 136-141. ISSN 0022-4596. E-ISSN 1095-726X
Výzkumný záměr: CEZ:AV0Z10100521
Klíčová slova: CeO₂ * ε-Fe₂O₃ * high coercivity * iron oxide polymorphs * phase transitions
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 2.040, rok: 2012
http://www.sciencedirect.com/science/article/pii/S0022459612001879

We have investigated the processes leading to the formation of the Fe2O3 and CeO2 nanoparticles in the SiO2 matrix in order to stabilize the ε-Fe2 O3 as the major phase. The samples with two different concentrations of the Fe were prepared by sol–gel method, subsequently annealed at different temperatures up to 1100°C, and characterized by the Mössbauer spectroscopy, Transmission Electron Microscopy (TEM), Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray analysis (EDX) and magnetic measurements. The evolution of the different Fe2O3 phases under various conditions of preparation was investigated, starting with the preferential appearance of the γ phase for the sample with low Fe concentration and lowe annaling temperature and stabilization of the major ε phase for high Fe concentration and high annealing temperature, coexisting with the most stable α phase.
Trvalý link: http://hdl.handle.net/11104/0007300