Structure and magnetic properties of colossal magnetoresistance compound Tb0.5Sr0.5CoO3

The structure and the magnetic properties of the doped rare earth cobaltite systems are of recent interest owing to the CMR phenomenon that occur in them. In this paper, we investigate the structure and magnetic properties of Tb_0.5Sr_0.5CoO₃ solid solution, for the first time, using neutron powder diffraction technique. The sample Tb_0.5Sr_0.5CoO₃ is found to crystallize in orthorhombic (Pbnm) symmetry. The unit cell volume and Co—O bond length reduce with temperature. The calculatede _g bandwidth obtained from structural parameters turns out to be 0.989 eV. Low temperature neutron diffraction profiles exhibit a magnetic contribution to the fundamental Bragg peaks indicating a ferromagnetic ordering belowT _c. The results are compared with Co—O—Co bond angles and Co—O bond length of La_0.5Sr_0.5CoO₃, highlighting the ionic size effects on substitution of Tb ion for La in the compound.