Magnetoresistance of a (Î³-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 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.
J. A. Wiemann et al., "Magnetoresistance of a (Î³-Fe2O3)80Ag20 Nanocomposite Prepared in Reverse Micelles," Journal of Applied Physics, vol. 87, no. 9 III, pp. 7001-7003, American Institute of Physics (AIP), May 2000.
The definitive version is available at http://dx.doi.org/10.1063/1.372911
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