Low-field magnetoresistance in nanosized La0.7Sr0.3MnO3/Pr0.5Sr0.5MnO3 composites

Nanosized La0.7Sr0.3MnO3/Pr0.5Sr0.5MnO3 (LSMO1-xPSMOx) ceramic composites a re prepared using solid-sate sintering. Their microstructural, electro- and magnetotransport properties are characterized by means of various techniqu es. It is found that the antiferromagnetic/ferromagnetic coupling between P SMO/LSMO at low temperature and the weak ferromagnetic order of PSMO at hig h temperature results in enhanced low-field magnetoresistance (LFMR) of the composites. With increasing temperature up to 250 K the observed LFMR deca ys more slowly than that for pure LSMO and this behavior may be explained b y the spin coupling near boundaries between LSMO and PSMO grains. (C) 2001 American Institute of Physics.