Magneto-transport Properties of La0.7Sr0.3Mn1+dO3-Manganese Oxide Composites Prepared by Liquid Phase Sintering

Abstract

Significantly enhanced low-field magnetoresistance (LFMR) and maximum dMR/dH {<TEX>$(dMR/dH)_{max}$</TEX>} values were successfully achieved from <TEX>$La_{0.7}Sr_{0.3}MnO_3$</TEX>(LSMO)-manganese oxide composite samples prepared by liquid phase sintering, compared with those of the same composites prepared by solid state reaction. For this study, pure LSMO and LSMO-manganese oxide composites with various nominal compositions of (1-x)LSMO-<TEX>$xMn_2O_3$</TEX> (x = 0.1, 0.2, 0.3, 0.4, and 0.8) were sintered at <TEX>$1450^{\circ}C$</TEX>, above the eutectic temperature of <TEX>$1430^{\circ}C$</TEX>, for 1 h in air. The highest LFMR value of 1.28% with the highest <TEX>$(dMR/dH)_{max}$</TEX> value of 21.1% <TEX>$kOe^{-1}$</TEX> was obtained from the composite sample with x = 0.3 at 290 K in 500 Oe. This enhancement of LFMR and <TEX>$(dM</TEX><TEX>R/dH)_{max}$</TEX> values is ascribed to efficient suppression of magnetic disorder at the LSMO grain boundary, by forming a characteristic LSMO-manganese eutectic structure.