Ferroelectric and flexible barrier resistive switching of epitaxial BiFeO3 films studied by temperature-dependent current and capacitance spectroscopy

The resistive switching of epitaxial ferroelectric BiFeO3 thin films was investigated by the combined current and capacitance spectroscopy, in addition with the piezoresponse force microscopy and conducting atomic force microscopy. A strong correlation between the resistance states and the capacitance states was found in the temperature range from 77 to 300 K, revealing the role of interface traps. It is demonstrated that the trap-assisted current transport contributes to the large ON current of the ferroelectric and flexible barrier resistive switching. The combination of ferroelectric polarization reversal, electro-migration of oxygen vacancies, and interface traps leads to the nonvolatile memory performance with the ON/OFF ratio of 102 for [105 s and the endurance of over 8000 cycles at room temperature.