Broad temperature range of resistance and magnetoresistance of multi-phase nanocomposites La1-x Sr x MnO3

Based on the ubiquitous existence of phase separation in the A1-x B x MnO3 system, using Mn(CH3COO)2.4H2O to react with SrCO3 and La2O3, we obtained multi-phase nanocrystalline manganese perovskites with nominal composition of La1-x Sr x MnO3 by a low temperature synthesis approach. The grain size of the as-prepared samples is estimated to be about 70 nm by using Scherrer formula and the full width at half maximum (FWHM) of X-ray diffraction lines. And two magnetic transitions were observed in AC susceptibility measurement, which should be related to the coexistence of the two phases in the fine grains. Through modulating the synthesis temperature, the grain size of the composites can be controlled from 70 to 240 nm, and the magnetic transition temperature varies from 273 K to 373 K, correspondingly. The inter-diffusion between the two phases was under control, and a broad temperature range of flat resistance and magnetoresistance near room temperature were obtained