Ionic conductivity and dielectric relaxation studies of a low-temperature form of silver zinc phosphate

Abstract Polycrystalline α-AgZnPO4 was prepared by the conventional solid-state reaction method. X-ray diffraction analysis at room temperature indicated the formation of a single phase hexagonal structure (space group P63). It crystallizes with a structure similar to those of high-temperature NaCoPO4 and KZnPO4. Besides, all vibration modes of tetrahedral PO4 appeared in the Raman spectrum. Two phase transitions at (438, 462) K were obtained by means of Differential scanning calorimetry (DSC). Furthermore, the electrical conductivity and the dielectric properties of this material were analyzed by means of the impedance spectroscopy technique, in a frequency ranging from 209 Hz to 1 MHz and temperature range (395–526) K. The phase transition observed in the calorimetric study was confirmed by the σdc and fpvariation as a function of temperature. The conduction mechanism was interpreted by the CBH model in phase I and II and by the NSPT model in the phase III.