AC conductivity and mechanism of conduction study of α-Sr2P2O7 using impedance spectroscopy

The ceramic sample Sr2P2O7 was prepared by a solid-state reaction technique at high temperature. Electrical properties and modulus analysis were studied using complex impedance spectroscopy in the frequency range 200 Hz?5 MHz and temperature range 602-714 K. The difference of the value of activation energy for the bulk obtained from analysis of equivalent circuit (0.81 eV) and modulus relaxation (0.69 eV) confirms that the transport is not due from a simple hopping mechanism. The average of the power law exponent s is reasonably interpreted by the overlapping large polaron tunneling (OLPT) model. The mechanism of conduction is probably due from the displacements of the Sr2+ ion in the tunnel-type cavities along the b axis.