High-Speed and Multi-Bit Resistive Switching Brought about by Migration of Hydrogen Ions in Resistive Random Access Memory Consisting of Bi2Sr2CaCu2O8+delta Single Crystal

We clarified that the resistive switching effect in transition metal oxides (TMOs) is caused by redox reaction due to the migration of oxygen ions of the oxygen-depleted layer formed at the interface between electrode and TMO. Additionally, we discovered that the resistive switching effect can be developed by redox reaction in a broad sense that is not restricted in oxygen migration. Hydrogen ions were efficiently introduced into Bi₂Sr₂CaCu₂O_8+δ (Bi-2212) single crystal with the assistance of the catalytic effect of Pt. The resistance switching which has the opposite relation between the polarity of the applied voltage and the resultant resistance change to that observed in Bi-2212 with no hydrogen introduction was observed. Characteristics of the resistive switching by migration of hydrogen ions were evaluated and, as a result, high applicability to a multi-bit application, low energy consumption, and very fast operation within 5 ns were revealed.