Electrical transport and low field magnetoresistance in doped perovskite composites

The granular composite system (1−x) La2/3(Ca2/3Sr1/3)1/3MnO3 (LCSMO)/x Cr2O3 was fabricated by the conventional solid-state reaction method, and the electrical transport and low field magnetoresistance of the composites were investigated. The results show that the content of Cr2O3 has appreciable effect on both the electrical transport and magnetoresistive properties of the composite system. With increase of Cr2O3 content the resistance increases; and the insulate-metal transition temperature shifts towards low temperature range. The magnetoresistance of the composite is enhanced in a wide temperature range in contrast with the pure LCSMO. It is indicated that the value of magnetoresistanc of the sample with x=8% attain to 20% at 10K under 0.3T magnetic field. The results were discussed by using the spin polarized tunneling mechanism.