Unipolar resistive switching in cobalt titanate thin films

We report giant resistive switching of the order of 10(4), long-time charge retention characteristics up to 10(4) s, non-overlapping SET and RESET voltages, Ohmic in low-resistance state (LRS) and space charge limited current (SCLC) mechanism in high-resistance state (HRS) properties in polycrystalline perovskite cobalt titanate (CoTiO3 similar to CTO) thin films. Impedance spectroscopy study was carried out for both LRS and HRS states which illustrates that only bulk resistance changes after resistance switching, however, there is a small change (< 10% which is in the pF range) in the bulk capacitance value in both states. These results suggest that in the LRS state current filaments break the capacitor in many small capacitors in a parallel configuration which, in turn, provides the same capacitance in both states even if there was a 90-degree change in phase angle and an order of change in the tangent loss. Copyright (C) EPLA, 2017