Electrical properties and magnetoelectric effect measurement in La0.7Ca0.2Sr0.1MnO3/xCoFe2O4 composites

Composites with compositions La0.7Ca0.2Sr0.1MnO3 (LCSMO)/xCoFe2O4 (CFO) were prepared by a standard ceramic technique. The structure and morphology of the composites have been studied by the X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The XRD and SEM results indicate that no reaction occurs between LCSMO and CFO grains, and that CFO segregates mostly at the grain boundaries of LCSMO. The variation in resistivity with temperature has been studied and shows a semi-conducting behavior, furthermore the composites exhibit metallic percolation threshold at x = xP = 8%. The magnetic moment (sigmaS) changed with the increase of CFO. Curie temperature (TC) is a dividing point; T < TC, sigmaS decreases with CFO content increasing, while T > TC, sigmaS changes contrarily with the addition of CFO. The magnetoresistance (MR) effect is enhanced at a wide temperature range in an applied magnetic field (3 kOe). The spin-polarized tunneling and the spin-dependent scattering may be attributed to the enhanced low-field magnetoresistance (LFMR) effect.