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 a me mory effect. Positive or negative voltage pulses can switch the resistance of the oxide films between a low- and a high-impedance state in times short er than 100 ns. The ratio between these two states is typically about 20 bu t can exceed six orders of magnitude. Once a low-impedance state has been a chieved it persists without a power connection for months, demonstrating th e feasibility of nonvolatile memory elements. Even multiple levels can be a ddressed to store two bits in such a simple capacitor-like structure. (C) 2 000 American Institute of Physics. [S0003-6951(00)04327-8].