Dielectric relaxation in laser ablated polycrystalline ZrTiO₄ thin films

Abstract

Relaxation and conduction mechanisms under small ac fields of laser ablated ZrTiO₄ thin films were analyzed in the light of impedance and modulus spectroscopy. The overall dielectric properties were mainly dominated by a Maxwell-Wagner type of relaxation with grains and the grain boundary two distinct parts of the circuit. Each of these parts was found to follow the universal power law of frequency dispersion. The modulus plot confirmed that the capacitive parts were relatively independent of the frequency and temperature, whereas the impedance and ac conduction studies exhibited significant temperature and frequency dependence. The conduction inside the grains was suggestive of a hopping mechanism through various defect sites whereas the interface barrier potential dictated grain boundary conduction.