Magnetovolume effect in the paramagnetic phase of Sm 1− xSr xMnO 3 ( x=0.45, 0.33) compounds

Abstract

Thermal expansion and magnetostriction measurements in high pulsed magnetic fields up to 13 T, have been performed on polycrystalline samples of the mixed valence manganese oxides Sm 1− x Sr x MnO 3 ( x=0.45 and 0.33), from room temperature to 4.2 K. In the case of Sm 0.55Sr 0.45MnO 3, the large volume magnetostriction suggests that “magnetic polarons” formation is the origin of the colossal magnetoresistance observed in this compound.