Magnetoresistance in Metallic Crystals of La_1-<i>x</i>Sr_<i>x</i>CoO₃

Abstract

Magnetotransport properties have been investigated for metallic crystals of La 1- x Sr x CoO 3 ( x =0.20 and 0.30) with perovskite structure. Around the ferromagnetic transition temperature ( T c ), fairly large negative magnetoresistance (MR) has been found. The magnitude of the MR is proportional to square of the magnetization above T c and appears to be enhanced as the metal-insulator compositional phase boundary is approached. The results are discussed in terms of the double exchange mechanism.