Ba-Doping Effect on Ca Sites of La_(0.5)Ca_(0.5)MnO_3

Single-phase polycrystalline samples of La0.5Ca0.5-xBa.MnO3 (0.15≤x≤0.5) were fabricated by the solid state reaction method. With increasing the content of Ba doping, the structural transition occurs from cubic to orthorhombic. The measurement of resistance as a function of temperature under zero field shows that the samples of lower doping behave a semiconducting behavior in the whole studied temper ature range, and a transition from semiconducting to metallic states appears in the samples x≥0.14. The transition moves toward the high temperature region with increasing the doping content. The role of Ba doping on the Ca sites was discussed on the basis of analyzing the experimental data.