Magneto-transport Properties of La 0.7 Sr 0.3 Mn 1+d O 3 -Manganese Oxide Composites Prepared by Liquid Phase Sintering

Significantly enhanced low-field magnetoresistance (LFMR) and maximum dMR/dH {(dMR/dH) max } values were successfully achieved from La 0.7 Sr 0.3 MnO 3 (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?xMn₂O₃ (x = 0.1, 0.2, 0.3, 0.4, and 0.8) were sintered at 1450°C, above the eutectic temperature of 1430°C, for 1 h in air. The highest LFMR value of 1.28% with the highest (dMR/dH) max value of 21.1% kOe ?1 was obtained from the composite sample with x = 0.3 at 290 K in 500 Oe. This enhancement of LFMR and (dMR/dH) max values is ascribed to efficient suppression of magnetic disorder at the LSMO grain boundary, by forming a characteristic LSMO-manganese eutectic structure.