Structural, electrical, magnetic and magnetotransport properties of La0.7Ca0.18Ba0.12Mn0.95Sn0.05O3 manganite prepared with different quenching processes

Structural, microstructural, magnetic, electrical and magneto-transport properties of La0.7Ca0.18Ba0.12Mn0.95Sn0.05O3 manganite powders, prepared by the solid state method, were investigated. Two quenching processes were performed on the samples: quenching in air and quenching to 77 K in liquid nitrogen. X-ray diffraction patterns refinement revealed that the samples crystallized in the orthorhombic structure. The scanning electron microscopy micrographs presented granular characters. The magnetization vs temperature plot showed a paramagnetic-ferromagnetic transition. The inverse susceptibility chi(-1)(T) deviation from the Curie-Weiss law revealed the existence of the phase above T-C in the nitrogen-quenched sample. The hysteresis cycles reveal that the samples are ferromagnetic at 1.8 K and paramagnetic at 300 K. The resistivity curves exhibit a ferromagnetic-metallic to paramagnetic-insulating transition. The magnetoresistance increased slightly in the sample quenched to 77 K in N-2.