Coexistence of unipolar and bipolar resistive switching behaviors in NiFe_2O_4 thin film devices by doping Ag nanoparticles

摘要

The coexistence of unipolar and bipolar resistive switching (RS) behaviors of Ag-nanoparticles (Ag-NPs) doped NiFe2O4 (NFO) based memory devices was investigated. The switching voltages of required operations in the unipolar mode were smaller than those in the bipolar mode, while ON/OFF resistance levels of both modes were identical. Ag-NPs doped NFO based devices could switch between the unipolar and bipolar modes just by preferring the polarity of RESET voltage. Besides, the necessity of identical compliance current during the SET process of unipolar and bipolar modes provided an additional advantage of simplicity in device operation. Performance characteristics and cycle-to-cycle uniformity ( 10 3 cycles) in unipolar operation were considerably better than those in bipolar mode ( 10 2 cycles) at 25 degrees C. Moreover, good endurance ( 600 cycles) at 200 degrees C was observed in unipolar mode and excellent nondestructive retention characteristics were obtained on memory cells at 125 degrees C and 200 degrees C. On the basis of temperature dependence of resistance at low resistance state, it was believed that physical origin of the RS mechanism involved the formation/rupture of the conducting paths consisting of oxygen vacancies and Ag atoms, considering Joule heating and electrochemical redox reaction effects for the unipolar and bipolar resistive switching behaviors. Our results demonstrate that 0.5% Ag-NPs doped nickel ferrites are promising resistive switching materials for resistive access memory applications. Published by AIP Publishing.