Enhanced non-linear current-voltage response of Te-doped calcium copper titanate ceramics

The influence of partial replacement of Ti4+ ions by Te4+ in calcium copper titanate lattice on dielectric and non-linear current- voltage (I-V) characteristics was systematically studied. There was a remarkable increase in the values of the nonlinear coefficient (α) with Te4+ doping concentration in CaCu3Ti4-xTexO12 (where, x=0, 0.1, 0.2).For instance, the α values increase from 2.9 (x=0) to 22.7 (x=0.2) for ceramics sintered at 1323 K/8 h. The room temperature value of current density (J) at the electrical field of 250 V/cm for CaCu3Ti3.8Te0.2O12 ceramics is almost 400 times higher than that of the pure CaCu3Ti4O12 ceramics sintered at 1323 K. A systematic investigation into I-V behaviour as a function of temperature gave an insight into the conduction mechanisms of undoped and doped ceramics of calcium copper titanate (CCTO). The calculated potential barrier value for doped ceramics (~ 0.21 eV) dropped down to almost one third that of the undoped ceramics (~ 0.63 eV).