Non-Ohmic properties of MgTiO3 doped CaCu3Ti4O12 thin films deposited by magnetron sputtering method

Abstract

CaCu3Ti4O12-xMgTiO3 (x = 0, 0.05, 0.1 and 0.2) thin films were prepared through magnetron sputtering method and sintered at 850 °C for 1 h. Second phase of CuO and TiO2 were detected in MgTiO3 doped ceramic targets and CaTiO3 phase was observed when x = 0.2. SEM results showed that grain size increased with MgTiO3 doping, which is corresponding to the decrease of threshold voltage. Remarkable non-Ohmic behaviors of all samples were observed at different temperatures. Nonlinear coefficient increased from 2.803 (x = 0) to 3.799 (x = 0.2) and Schottky barrier height increased firstly then decreased as MgTiO3 doping. Double Schottky barrier model was used to explain the non-Ohmic characteristic of CCTO thin films.