Unipolar resistive switching in cobalt titanate thin films

TL;DR

This paper demonstrates giant unipolar resistive switching in cobalt titanate thin films with excellent charge retention and distinct electrical states, revealing filamentary conduction and stable capacitance behavior.

Contribution

It reports the first observation of giant unipolar resistive switching in CoTiO3 thin films with detailed electrical and impedance analysis.

Findings

Resistive switching ratio of 10^4

Charge retention up to 10^4 seconds

Bulk resistance change dominates switching behavior

Abstract

We report giant resistive switching of an order of 104, long-time charge retention characteristics up to 104 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 ~ 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 pF range) in the bulk capacitance value in both states. These results suggest that in 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 there was 90 degree changes in phase-angle and an order of change in the tangent loss.