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Magnetism of sol-gel fabricated CoFe2O4/SiO2 nanocomposites
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SYSNO ASEP 0027392 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Ostatní články Title Magnetism of sol-gel fabricated CoFe2O4/SiO2 nanocomposites Title Magnetické vlastnosti nanokompozitů CoFe2O4/SiO2 připravených metodou sol-gel Author(s) Vejpravová, J. (CZ)
Plocek, Jiří (UACH-T) RID, ORCID, SAI
Nižňanský, Daniel (UACH-T) ORCID, SAI, RID
Hutlová, Alžběta (UACH-T)
Rehspringer, J.L. (FR)
Sechovský, V. (CZ)Source Title Journal of Applied Physics. - : AIP Publishing - ISSN 0021-8979
Roč. 97, č. 12 (2005), 124304/1-124304/7Number of pages 7 s. Language eng - English Country US - United States Keywords nanocrystalline iron particles ; sol-gel method ; ferrite nanoparticles Subject RIV CA - Inorganic Chemistry R&D Projects KJB4032402 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) CEZ AV0Z40320502 - UACH-T (2005-2011) Annotation Details of synthesis and characterization of sol-gel-produced CoFe2O4 nanoparticles embedded in the amorphous SiO2 matrix are presented together with results of an extended magnetization study of these materials. The particle size was found to increase from 6 to 15 nm by varying the temperature of a subsequent annealing from 800 to 1100 degrees C. All samples exhibited superparamagnetic behavior with values of the blocking temperature T-B increasing with the particle size. At temperatures above T-B the magnetization curves follow the expected Langevin scaling of M vs H/T, which is consistent with the formation of the superparamagnetic state. For T < T-B, the coercivity field H-c was found to be proportional to root T and the frequency-dependent ac susceptibility was found to obey the Neel-Arrhenius law. Both observations are compatible with a model of noninteracting randomly oriented single-domain particles. Workplace Institute of Inorganic Chemistry Contact Jana Kroneislová, krone@iic.cas.cz, Tel.: 311 236 931 Year of Publishing 2006
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