Magnetoresistance of a (γ-Fe2O3)80Ag20 nanocomposite prepared in reverse micelles

The magnetic and transport properties of a (γ-Fe2O3)80Ag20 nanocomposite, prepared by a reverse micelle technique, have been studied. γ-Fe2O3 nanoparticles and Ag particles were individually synthesized in reverse micelles. The nanocomposite material was then prepared by mixing the two different par...

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Bibliographic Details
Published in:Journal of applied physics 2000-05, Vol.87 (9), p.7001-7003
Main Authors: Wiemann, Joan A., Carpenter, Everett E., Wiggins, Jason, Zhou, Weilie, Tang, Jinke, Li, Sichu, John, Vijay T., Long, Gary J., Mohan, Amitabh
Format: Article
Language:English
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Summary:The magnetic and transport properties of a (γ-Fe2O3)80Ag20 nanocomposite, prepared by a reverse micelle technique, have been studied. γ-Fe2O3 nanoparticles and Ag particles were individually synthesized in reverse micelles. The nanocomposite material was then prepared by mixing the two different particles in a γ-Fe2O3/Ag molar ratio 80/20. The morphology of the nanoparticles was examined with transmission electron microscopy. Mössbauer spectra revealed no obvious presence of any divalent iron. Zero field cooled and field cooled magnetic susceptibilities indicated a blocking temperature of about 40 K. Negative magnetoresistance was observed resembling that in ball milled γ-Fe2O3/Ag nanocomposites. However, the magnitude of the negative magnetoresistance is smaller and is ∼2.2% at 220 K and 9 T. Two possible mechanisms, spin-dependent hopping and tunneling across magnetic barriers, are discussed.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.372911