Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3 O4 and Fe3 C nanoparticles dispersed in a graphite matrix

Guskos, N; Anagnostakis, EA; Likodimos, V; Bodziony, T; Typek, J; Maryniak, M; Narkiewicz, U; Kucharewicz, I; Waplak, S

dc.contributor.author	Guskos, N	en
dc.contributor.author	Anagnostakis, EA	en
dc.contributor.author	Likodimos, V	en
dc.contributor.author	Bodziony, T	en
dc.contributor.author	Typek, J	en
dc.contributor.author	Maryniak, M	en
dc.contributor.author	Narkiewicz, U	en
dc.contributor.author	Kucharewicz, I	en
dc.contributor.author	Waplak, S	en
dc.date.accessioned	2014-03-01T01:22:24Z
dc.date.available	2014-03-01T01:22:24Z
dc.date.issued	2005	en
dc.identifier.issn	0021-8979	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16552
dc.subject.classification	Physics, Applied	en
dc.subject.other	ac conductivity	en
dc.subject.other	Interparticle interactions	en
dc.subject.other	Magnetic nanoparticles	en
dc.subject.other	Polymer composite	en
dc.subject.other	Spin polarization	en
dc.subject.other	Activation energy	en
dc.subject.other	Electric conductivity	en
dc.subject.other	Ferromagnetic resonance	en
dc.subject.other	Magnetic anisotropy	en
dc.subject.other	Magnetization	en
dc.subject.other	Nanostructured materials	en
dc.subject.other	Particle size analysis	en
dc.subject.other	Polarization	en
dc.subject.other	Single crystals	en
dc.subject.other	Superparamagnetism	en
dc.subject.other	Thin films	en
dc.subject.other	X ray diffraction	en
dc.subject.other	Iron compounds	en
dc.title	Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3 O4 and Fe3 C nanoparticles dispersed in a graphite matrix	en
heal.type	journalArticle	en
heal.identifier.primary	10.1063/1.1836855	en
heal.identifier.secondary	http://dx.doi.org/10.1063/1.1836855	en
heal.identifier.secondary	024304	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	Ferromagnetic resonance (FMR) and ac conductivity have been applied to study a polymer composite containing as filler a binary mixture of magnetite (Fe3O4) and cementite (Fe3C) nanoparticles (30-50 nm) dispersed in a diamagnetic carbon matrix, which was synthesized by the carburization of nanocrystalline iron. Ac conductivity measurements showed thermally activated behavior involving a range of activation energies and power law frequency dependence at high frequencies similar to conducting polymer composites randomly filled with metal particles. Ferromagnetic resonance measurements revealed a relatively narrow FMR line at high temperatures indicating the presence of ferromagnetic nanoparticles, where thermal fluctuations and interparticle interactions determine the FMR temperature variation. An abrupt change of the FMR spectra was observed at T<81 K (DeltaTless than or equal to1 K) coinciding with a sharp anomaly resolved in the temperature derivative of the ac conductivity. This behavior is attributed to the Verwey transition of Fe3O4 nanoparticles, where the concurrent skin depth variation unveils the FMR of large magnetite conglomerates and thus allows discriminating their contribution from relatively isolated nanoparticles. (C) 2005 American Institute of Physics.	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	Journal of Applied Physics	en
dc.identifier.doi	10.1063/1.1836855	en
dc.identifier.isi	ISI:000226700500076	en
dc.identifier.volume	97	en
dc.identifier.issue	2	en