Fabrication and electrical investigations of Pb-doped SaTiO3 ceramics

Electrical properties of Pb doped BaTiO3; PBT are investigated in the wide range of temperatures (40 -700 degrees C) at 1 kHz frequency. PBT ceramics were fabricated through solid state sintering method. Pre fired BaTiO3 prepared with Ba/Ti molar ratio of 0.98 was doped with PbCO3 (<1 mole %). XRD patterns indicated perovskite phase with tetragonal structures (P4mm). Morphological studies (SEM) revealed grain development with increasing lead contents. With lead doping and its variation, Curie temperature (Tc) was shifted from 120 to 200 degrees C with broad dielectric constant peaks and dielectric anomalies with relaxor behavior were observed. Resistivity decreased with increasing temperature, all specimens showed semiconductor behavior with negative temperature coefficient of resistivity (NTCR) characteristics. Mobility of electrons increased with thermal activation due to hopping of charge carriers from one site to another. Ohmic conductivities and associated activation energies were evaluated by impedance spectroscopy. Conductivity followed the Arrhenius law with E-a = 1.187-1.169 eV which can be attributed to the ionic conduction owning to doubly ionized oxygen vacancies. Well-defined hysteresis P-E loops measured at room temperature depicted ferroelectric properties of the materials. (C) 2017 Elsevier B.V. All rights reserved.