Abstract
Mn‐modified Pb~0.92~La~0.08~(Zr~0.65~Ti~0.35~)O~3~ (PLZT) was prepared chemically by a coprecipitate method using their respective nitrate salts and isopropoxides. Differential thermal analysis (DTA) and X‐ray analysis clearly show the formation of PLZT single rhombohedral phase for samples calcined beyond 750 °C. Uniform grain distribution was observed from scanning electron microscopic (SEM) studies and grain size was found to increase with Mn doping up to x = 0.08 and then decreased. Dielectric measurement shows the decrease in peak transition temperature (T~C~) with Mn doping up to x = 0.12 and then increase along with a sharp rise in dielectric maxima. A diffuse dielectric dispersion is observed in all the compositions. A detailed dispersion study was carried out using the Vogel–Fulcher empirical relation, a universal relaxation law and the Havriliak–Negami function. The Vogel–Fulcher relation fitting parameters of activation energy and freezing temperature were found to decrease with Mn doping up to x = 0.12, which was expected to be the cause of the variation of T~C~. The exponent m of the universal relaxation law was found to increase with Mn doping and also with increasing temperature, which suggests an enhanced conducting nature of the composition. In the Havriliak–Negami function, the Cole–Cole fitting parameter α was found to increase and β was found to decrease with Mn doping and also with temperature, which suggests that the dispersion behavior changed from Cole–Cole type to Cole–Davidson type with Mn doping in PLZT. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)