Non-uniform behavior of La0.7Sr0.3Co1−Mn O3 (y=0.3 and 0.5) compounds

Abstract La 0.7 Sr 0.3 Co 1− y Mn y O 3 compounds ( y =0.3 and 0.5) have been studied by M ( H ), χ ac ( T ) measurements. As for y =0.3, analyses of the high-field portion of the M ( H ) curves indicate the coexistence of a ferromagnetic and a paramagnetic phase. These results indicate that the system is non-uniform, consisting of small isolated ferromagnetic regions in a non-ferromagnetic matrix. Anomalous M ( H ) curves and a frequency-dependent χ ac ( T ) appear at a temperature below 40 K, which signals a low-temperature glassy magnetic phase.