Oxygen-vacancy-mediated Negative Differential Resistance in La and Mg   co-substituted BiFeO3 Thin Film
  The conductive characteristics of Bi0.9La0.1Fe0.96Mg0.04O3(BLFM) thin film are investigated at various temperatures and a negative differential resistance (NDR) is observed in the thin film, where a leakage current peak occurs upon application of a downward electric field above 80 oC. The origin of the NDR behavior is shown to be related to the ionic defect of oxygen vacancies (VO..) present in the film. On the basis of analyzing the leakage mechanism and surface potential behavior, the NDR behavior can be understood by considering the competition between the polarized distribution and neutralization of VO... 
Qingqing Ke, Amit Kumar, Xiaojie Lou, Kaiyang Zeng and John Wang
cond-mat.mtrl-sci