Low field magnetoresistance in La_0.67Sr_0.33-x□_xMnO₃perovskite system

Abstract

Abstract We have studied magnetization, resistivity and magnetoresistance in polycrystalline La0.67Sr0.33-x□xMnO3 samples where 0 ≤x ≤0.33. With varying x, powder X-ray diffraction patterns could be indexed in a rhombohedral and an orthorhombic perovskite structure. As the A-site vacancy content increases, the resistivity of samples increases and the magnetic transition temperature shifts to lower temperature. The field dependence of magnetoresistance shows the presence of two distinct regimes. At low temperature the magnetoresistance was observed to be strongly dependent on the magnetization reaching a 17% variation of the resistivity in a low field of 2kOe.