Magnetic properties and oxygen migration induced resistive switching effect in Y substituted multiferroic bismuth ferrite

Abstract

Multiferroic Y-doped BiFeO₃ (BY10FO) thin films were deposited on FTO coated glass substrate using sol–gel spin coating technique. Y-doping causes structural distortion without changing the structure of the parent BiFeO₃ (rhombohedral: R3c). The M–H hysteresis curve reveals that the BY10FO film exhibits saturation magnetization at a low-coercive field by suppressing the spiral spin modulated structure. The bipolar resistive switching behavior has been investigated on a Ag/BY10FO/FTO hetero-structure through conventional I–V curve measurements and the device can produce an ON/OFF ratio of around 12 over 30 complete testing cycles. The space charge limited current and Schottky barrier emission conduction mechanism play a crucial role in switching the states between HRS and LRS. The impedance spectroscopy analysis at HRS and LRS confirms the significant degradation of resistance from MΩ to kΩ. The switching mechanism in the hetero-structure is due to migration and recombination of oxygen vacancies present in the film. The non-degradation of the Ag/BY10FO/FTO device after several testing cycles confirms that the switching of resistance between ON and OFF states is reproducible, reversible and controllable to be used for possible future non-volatile resistive random access memory application.