Effects of Mn doping on the conduction mechanism and dielectric nonlinearity of Na_0.5Bi_0.5TiO₃ thin film

Abstract

In this work, the conduction mechanism and dielectric nonlinearity of undoped and Mn-doped Na0.5Bi0.5TiO3 (NBT) films were investigated. The potential conduction mechanism in relatively low electric field region should be dominated by the Hopping conduction rather than the typical Ohmic conduction. In high electric field region, the conduction mechanism was dominated by P-F and Schottky emission. The enhancement of electrical insulation of NBT film after Mn doping was shown to be result from the decrease in oxygen vacancy and the elevation of conduction energy barrier. Furthermore, significant improvements in the nonlinearity of both the dielectric constant and polarization of Mn-doped NBT film were observed, as indicated by the results of Rayleigh fitting and first-order reversal curve (FORC) distributions. Such enhancements were attributed to the reduced in domain wall pinning, decreased interference of electrostatic potential and improved leakage characteristic.