Reproducible switching effect in thin oxide films for memory applications

Thin oxide films with perovskite or related structures and with transition metal doping show a reproducible switching in the leakage current with memory effect. Positive or negative voltage pulses can switch the resistance of the oxide films between a low and a high-impedance state in times shorter than 100 ns. The ratio between these two states is typically about 20 but can exceed six orders of magnitude. Once a low-impedance state has been achieved it persists without power connection for months, demonstrating the feasibility of nonvolatile memory elements. Even multiple levels can be addressed to store two bits in such a simple capacitor-like structure.