Structural and ac conductivity studies of sodium tetralead triphosphate compound

Abstract Sodium tetralead triphosphate NaPb 4 (PO 4 ) 3 compound was synthesized by the solid-state reaction method, characterized through X-ray powder diffraction, Raman and electrical impedance spectroscopy. A Rietveld analysis of powder X-ray diffraction has shown that the title compound crystallizes in the hexagonal system at room temperature, space group P 6 3 / m . A pellet of 92% density was used for the electrical measurements. All electrical measurements of real and imaginary components of the impedance parameters were made over a wide range of temperature (598–720) K and frequency (209 Hz–1 MHz) using a Tegam 3550 impedance analyzer interfaced to a compatible computer. Ac conductivity data affirm that for high frequencies σ ac is proportional to ω s . The frequency exponent values increase with increasing temperature revealing that the non-overlapping small polaron tunneling is the appropriate conduction mechanism.