Hydrogen annealing effects on polycrystalline La0.67Ba0.33MnO3 compound

Abstract Upon annealing polycrystalline La 0.67 Ba 0.33 MnO 3 bulk samples in flowing 95%Ar:5%H 2 mixed gas at 700 °C for different time, the insulator–metal transition temperature, T P and the amplitude of AC magnetic susceptibility were decreased first, then increased, finally decreased again. While the resistivity was increased monotonically. This anomalous behavior was explained by the combinational effects of oxygen loss and Ba ion vacancies caused by the segregation of Ba ion related impurity phase.