Nonvolatile bipolar resistive switching behavior of epitaxial NdFeO_3-PbTiO_3 thin films grown on Nb:SrTiO_3(001) substrate

摘要

Epitaxial NdFeO_3-PbTiO_3 (NFPTO) thin films were fabricated on Nb-SrTiO_3(100) (NSTO) substrates of about 300 nm thickness by a sol-gel process. Nonvolatile bipolar resistive switching has been observed in the Pt/NFPTO/NSTO structure. The resistance ratio between the high-resistance state and the low-resistance state is about one order of magnitude. After degenerating for several minutes, each memory state is stably maintained and no further degradation occurs over 15000 s. X-ray photoelectron spectroscopy results suggest that the oxygen vacancies acting as trapping centers in the films play a significant role in the resistive switching mechanisms. Analysis of the current-voltage relationship demonstrates that the trap-controlled space-charge-limited current mechanism is of considerable Importance to the resistance switching.