Leakage Current Properties of Cation-Substituted BiFeO3 Ceramics

Cation-doped BiFeO3 ceramics were fabricated by sintering coprecipitated and calcined powders at 700-900 degrees C to study the effect of cation doping on the leakage current properties of the sintered samples. Among the dopants examined in this study, Ti4+, Sn4+, or Zr4+ doping was found to effectively reduce the leakage current of the samples. In particular, a marked decrease in the leakage current density was achieved at 10% Ti4+ doping, which also resulted in the structure change from rhombohedral to cubic. The codoping of Ti4+/Zn2+ ions or Ti4+/Ni2+ ions brought about a substantial reduction in the leakage current density of the bulk samples by about four or five orders of magnitude at a small doping amount of 2%. This can be explained by the combined effect of Ti4+ doping, which basically contributes to the decreased number of oxygen vacancies in the sample, and Zn2+ or Ni2+ doping, which might assist the homogeneous substitution of Ti4+ ions for the Fe3+ sites. (C) 2010 The Japan Society of Applied Physics