Improved magnetotransport in LCMO-Polymer (PPS) composite

Polymer embedded, La0.7Ca0.3MnO3/polyphenylene sulfide (LCMO)1−x/(PPS)x (with x∼0x∼0, 0.10, 0.20 and 0.30, xx is the weight fraction of PPS), composites were prepared and their magnetotransport properties were investigated. X-ray diffraction and scanning electron microscopy observations indicate that there is no reaction between the LCMO and PPS. It has been observed that the incorporation of PPS phase into the LCMO matrix sharply increases the resistivity and lowers the metal–insulator transition temperature (TIM). Magnetic measurement reveals that the ferromagnetic order of LCMO is suppressed by the addition of nonmagnetic PPS. The significant enhancement in magnetoresistance (MR) is observed at low temperature below 175 K for the composites with x=0.10x=0.10 and 0.20 with respect to pure LCMO at magnetic field H∼3kOe. We suggest that such enhancement in MR is because of spin disorder caused through enhanced spin-polarized tunneling at the grain boundaries in the composite samples.