Effect of High Resistivity Phase on Magnetoresistance of La0.7Ca0.2Sr0.1MnO3

La0.7Ca0.2Sr0.1MnO3/xCoFe(2)O(4) (LCSMO/xCFO) samples were prepared by solid state reaction method. X-ray diffraction (XRD), scanning electronic microscopy (SEM), vibrating sample magnetometer (VSM) and Dc four probed method were used to investigate the structure and properties. The results show that that CFO mainly segregated at the boundaries of LCSMO grains, which did not change the structure of LCSMO. In the doping range of 0 similar to 0.35, the resistivity rises remarkably, furthermore, the resistivity versus appears double peaks with increasing CFO doping amount. While T-C is unchanged, T-C is a dividing point, the magnetization changed with the increase of CFO. The composites present a sizable magnetoresistance at much lower temperature than T-P when applied a small field (similar to 3 kOe), this is an extrinsic MR effect, and the magnetic scattering of polarized charge carriers may be responsible for enhanced extrinsic MR of the composites.