Solid State Ionics, Vol.303, 16-23, 2017
Electrical investigations of BaTiO3 ceramics with Ba/Ti contents under influence of temperature
Electrical properties of the solid state sintered BaTiO3 ceramics at 0.98 and 0.94 Ba/ri molar ratio are investigated perhaps for the first time in the wide range of temperatures (40-700 degrees C) at 1 kHz frequency. The studies were focused to find the controlling parameters, resistance and understanding of the conduction process. BaTiO3 ceramics were perovskite ferroelectric materials, showed cubic and tetragonal crystal structures (Pm-3m, P4MM) at room temperature. Thermogravimetric and differential scanning calorimetric analysis (TGA-DSC) revealed melting temperatures, weight losses and crystallization of the as ground powders. Curie temperature (T-c) increased from 120-130 degrees C with decreasing Ba/Ti contents. 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. At 0.98 molar ratio, BaTiO3 ceramics were found to be more conductive and less resistive. Conductivity followed Arrhenius Law with E-a = 0.2948-0.3284 and 0.967-1.189 eV which can be attributed to ionic conduction followed by single ionized and doubly ionized oxygen vacancies. Well defined hysteresis P-E loops under electric fields showed ferroelectric characteristics. (C) 2017 Elsevier B.V. All rights reserved.
Keywords:BaTiO3 ceramics;Ferroelectric materials;Curie temperature;Paraelectric regions;Ionic conduction