Quenching-promoted anomalous electromagnetic behaviors of polycrystalline La0.67Ba0.33MnO3 compound by hydrogen annealing

Anomalous annealing behaviors of insulator-metal transition temperature (TP) and ac magnetic susceptibility were investigated in different prepared polycrystalline La0.67Ba0.33MnO3 bulk samples which were annealed in a flow of 95%Ar:5%H2(AH) at 700 °C for different time, and the behaviors were effects of oxygen loss and Ba ion vacancies. The experiments indicated that different prepared samples had different speed of oxygen loss and Ba ion vacancies during AH annealing. Different prepared samples had different content of structure defects, especially for the quenching samples, in which there were high stress and high defect content, the speed of oxygen loss and Ba2+ vacancies were the fastest during AH annealing, that was to say that quenching promote the hydrogen annealing effects on polycrystalline La0.67Ba0.33MnO3 compound.