Magnetic properties of FeCo nanoparticles encapsulated in carbon

The as-prepared and heat treated iron/cobalt nanoparticles with r Co/Fe 0.08 and 1 were obtained by laser decomposition. At low temperatures all the materials are in a ferromagnetic blocked state. At higher temperatures (T > 200 K) the as-prepared materials exhibit superparamagnetic properties. I...

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Bibliographic Details
Published inJournal of physics. Conference series Vol. 200; no. 7; p. 072065
Main Authors Maryško, M, Fajgar, R, Šubrt, J, Murafa, N, Knížek, K
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.01.2010
Subjects
Cobalt
Ferromagnetic materials
Heat
Heat treatment
Hysteresis loops
Iron
Low temperature
Magnetic properties
Nanoparticles
Physics
Size distribution
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Summary:The as-prepared and heat treated iron/cobalt nanoparticles with r Co/Fe 0.08 and 1 were obtained by laser decomposition. At low temperatures all the materials are in a ferromagnetic blocked state. At higher temperatures (T > 200 K) the as-prepared materials exhibit superparamagnetic properties. In this case the nanoparticle size distribution deduced from the m(H) curves and from the difference between the FC and ZFC susceptibilities was compared with the TEM data. The heat treated materials have larger magnetizations and a maximum (161 emu/g) was achieved for the r 1 material heat treated at 900°. For this material an anomalous form of the hysteresis loop was explained in terms of a superposition of single and multi-domain magnetizations.
ISSN:1742-6596
1742-6588
1742-6596
DOI:10.1088/1742-6596/200/7/072065