Nonvolatile resistive switching in BiFeO3 thin films

Nonvolatile resistive switching has been observed in an Au/BiFeO3/Pt structure, where a Schottky contact and an Ohmic contact were formed at the Au/BiFeO3 and BiFeO3/Pt interface, respectively. By changing the polarity of the external voltage, the Au/BiFeO3/Pt is switched between two stable resistance states with a resistance ratio larger than two orders of magnitude. Based on a systematic investigation of its electrical properties with an emphasize on its transport characteristics, a model associated with the redistribution of oxygen vacancies and the formation of an electron hopping path is proposed, which agrees well with our experimental observations. In the present work we found that the electron hopping can be controlled and utilized to realize bipolar resistive switching, which is promising for future high density memory devices.