Dielectric and electrical properties of gadolinium-modified lead-zirconate-titanate system

The gadolinium (Gd) modified lead zirconate titanate (PbZr, TiO3) ceramics with Zr/Ti = 48/52 (i.e., near morphotropic phase boundary (MPB)) in a general chemical formula Pb-1 Gd-x(x) (Zr0.48Ti0.52)(1) (x/4) O-3 (PGZT; x = 0, 0.07, 0.10 and 0.12) have been synthesized using a high-temperature solid-state reaction method. Preliminary structural analysis using X-ray powder diffraction (XRD) shows the formation of a single-phase tetragonal structure of the compounds. Detailed studies of dielectric parameters of PGZT exhibit the diffuse phase transition but non-relaxor characteristics in the material for the higher concentration of gadolinium. The ac conductivity spectra of PGZT are found to obey Jonscher's universal power law. The electrical impedance parameters of PGZT (near MPB) were obtained in a wide range of temperature (25-500 degrees C) and frequency (1-1000 kHz) using complex impedance spectroscopy (CIS) technique. Detailed analysis of these parameters shows that bulk (grain) and grain boundary resistance have significant effect on the total impedance of the materials. Temperature dependence of hysteresis characteristics of PGZT confirms that the phase transition parameter of the material is strongly affected by the substitution of Gd at the Pb-sites. (C) 2014 Elsevier B.V. All rights reserved.