Developmental mechanism for the resistance change effect in perovskite oxide-based resistive random access memory consisting of Bi2Sr2CaCu2O8+δ bulk single crystal

Resistive random access memory (ReRAM) structures of M/Bi2Sr2CaCu2O8+delta (Bi-2212) bulk single crystal/Pt (M = Al, Pt) were prepared and their memory characteristics and superconducting properties were evaluated. The resistance change effect developed only in the Al/Bi-2212/Pt structure and was enhanced with decreasing critical temperature by annealing in Ar atmosphere. Due to the large resistance anisotropy of bulk Bi-2212 single crystals, the resistance change effect was confirmed to occur at the interface between the Al electrode and the Bi-2212 single crystal. These results indicate that introduction of an oxygen-depleted layer to the Bi-2212 single crystal is required to develop the resistance change effect, which could be achieved by the deposition of electrodes with low Gibbs free energy and raising the temperature to exceed the activation energy for oxygen ions to move from Bi-2212 to the electrode. A model is proposed to explain the resistive switching of perovskite oxide-based ReRAM by generation/recovery of the oxygen-depleted layer. The resistance change effect developed also in the Pt/Bi-2212/Au structure annealed in hydrogen gas, in which an oxygen-depleted layer is formed with the assistance of catalytic effect of Pt on the surface of the Bi-2212 at the Pt/Bi-2212 interface, proving the validity of the model. (C) 2011 American Institute of Physics. [doi:10.1063/1.3651465]