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 M -FC and zero field cooled M-ZFC below T-c X-ray and neutron diffraction mea surements have been also performed. The crystal structure of La0.5Sr0.5CoO3 at room temperature is rhombohedrally distorted perovskite belonging to th e space group R(3) over bar c (No. 167) with the a(-)a(-)a(-) type tilt sys tem. 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 tha t the octahedral tilting becomes smaller with the Ba substitution. (C) 2001 Published by Elsevier Science Ltd.