Crystal structure, electrical and magnetic properties of perovskites La0.5Sr0.5–xBaxCoO3 (x=0.0 and 0.25)

The resistivity and magnetization of La0.5Sr0.5–xBaxCoO3 (x=0.0 and 0.25) system have been investigated. The resistivity of La0.5Sr0.5–xBaxCoO3 has increased with Ba substitution. Magnetization curves of La0.5Sr0.5–xBaxCoO3 (x=0.0 and 0.25) have showed the large difference between field cooled MFC and zero field cooled MZFC below Tc. X-ray and neutron diffraction measurements have been also performed. The crystal structure of La0.5Sr0.5CoO3 at room temperature is rhombohedrally distorted perovskite belonging to the space group R3c (No. 167) with the a−a−a− type tilt system. From the results of powder X-ray and neutron Rietveld analysis, it is demonstrated that the lattice parameter along the a-axis increases and the rhombohedral angle decreases with the Ba substitution. It is also shown that the octahedral tilting becomes smaller with the Ba substitution.