Magnetization Processes of (La 0.7 Pb 0.3 MnO 3 ) 1−x (SiO 2 ) x Composites

The ceramic composites, (La0.7Pb0.3MnO3)1−x (SiO2) x , with diluted magnetic properties are prepared using solid-sate sintering route. Magnetization processes of (La0.7Pb0.3MnO3)1−x (SiO2) x composites are explored in this study. Ferromagnetism is gradually attenuated due to the magnetic dilution induced by the increase of SiO2 content. Clearly, irreversible behavior is observed in the zero-field cooling and the field cooling (ZFC–FC) curves at a low field of 100 Oe. Saturation magnetization decreases as x increases while ferromagnetic transition temperature remains around 346 K for all composites. All the composites exhibit ferromagnetic hysteresis behavior which can be modeled by the law of the approach to saturation in the form M=M S(1−a/H). The term a/H expresses the deviation of magnetization from saturation. The smaller factor a for La0.7Pb0.3MnO3-rich samples results in sharper square curve which should be associated with the long-range spin order of ferromagnetic coupling.