Homogeneous interface-type resistance switching in Au/La_0.67Ca_0.33MnO₃/SrTiO₃/F:SnO₂ heterojunction memories

La_0.67Ca_0.33MnO₃ thin films are fabricated on fluorine-doped tin oxide conducting glass substrates by a pulsed laser deposition technique with SrTiO₃ used as a buffer layer. The current-voltage characteristics of the heterojunctions exhibit an asymmetric and resistance switching behaviour. A homogeneous interface-type conduction mechanism is also reported using impedance spectroscopy. The spatial homogeneity of the charge carrier distribution leads to field-induced potential-barrier change at the Au-La_0.67Ca_0.33MnO₃ interface and a concomitant resistance switching effect. The ratio of the high resistance state to the low resistance state is found to be as high as 1.3?10⁴% by simulating the AC electric field. This colossal resistance switching effect will greatly improve the signal-to-noise ratio in nonvolatile memory applications.