Magnetoresistance of a [formula omitted] nanocomposite prepared in reverse micelles

Abstract

The magnetic and transport properties of a [formula omitted] nanocomposite, prepared by a reverse micelle technique, have been studied. [formula omitted] nanoparticles and Ag particles were individually synthesized in reverse micelles. The nanocomposite material was then prepared by mixing the two different particles in a [formula omitted] 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 [formula omitted] 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. © 2000, American Institute of Physics. All rights reserved.