Restoration hysteresis effect of nonlinear current–voltage behavior and negative resistance characteristics of sol–gel derived CaCu3Ti4O12 thin films

Abstract

CaCu3Ti4O12 (CCTO) thin film was prepared by sol–gel method. Obvious nonlinear I–V characteristics were presented. With the increase of sintering temperature, the threshold voltages of CCTO thin films significantly reduced. Restoration hysteresis effect was firstly reported, which means that once the nonlinear I–V behavior is presented after the applied voltage is greater than threshold, the reloading of voltage will not result in the nonlinear I–V behavior, but firstly in a negative resistance phenomenon and then in linearly increased current, in another word, there will be a V-type current with the increase of voltage. We believe that the nonlinear I–V characteristics is associated with the Schottky barrier at grain boundaries, and the increase of sintering temperature promotes the growth of grains, and the number of grain boundaries decrease correspondingly, which will decrease the threshold voltages. Tunnel junction model was used to give the explanation of nonlinear current–voltage behavior and restoration hysteresis effect.