Fluctuation Controlled Hopping of Bound Magnetic Polarons in ErAs:GaAs Nanocomposites

Abstract
Transport in ErAs:GaAs nanocomposites occurs via hopping of bound magnetic polarons between nanoparticles of magnetic semimetallic ErAs. A strong negative magnetoresistance, up to 3 orders of magnitude and strongly dependent upon ErAs particle size, is accompanied by a low field positive magnetoresistance. A model that features fluctuation controlled hopping captures this behavior.