Giant positive magnetoresistance in Fe doped In2O3 and InREO3 (RE=Eu,Nd) composites

Synthesis and characterization of Fe and rare earth (RE) (RE=Eu,Nd) codoped bulk In2O3 oxide are reported. Composites consisting of Fe-doped In2O3 and InREO3 phases were formed, as determined by x-ray diffraction and transmission electron microscopy, with particle sizes of 50–120 nm. The composites exhibit superparamagnetic and semiconducting behavior. A giant positive magnetoresistance is observed at low temperatures, reaching 81% and 50% at 5 K in Eu–Fe and Nd–Fe codoped samples, respectively.