Piezoelectric force microscopy study of local bipolar diode current dependence of preferential domain orientation in BiFeO3 thin films with different thicknesses

Local hysteretic diode currents depending on domain orientations have been observed in epitaxial BiFeO3 thin films. The mechanism behind the bilateral and unilateral current hysteresis as well as retention of the nanodomains has been discussed in the films with different thicknesses. Piezoelectric force microscopy investigations reveal principle of resistive property is the switchable polarization control of hysteretic diode currents other than the creation and rupture of the conductive paths in other resistive random access memories mediated by mobile charged defects. With the investigation of different leakage current models, it has been found that the space-charge limited current (SCLC) dominates the conduction.