Study of dielectric property, electric modulus and conduction phenomena of Sn-modified Ba_0.5Sr_0.5TiO₃ ceramics

Abstract

BST ceramics having a composition of Ba_0.5Sr_0.5Ti_1-xSn_xO₃ (x = 0.03) was prepared following a high-temperature solid state reaction route with BaCO₃, SrCO_3, TiO₂ and SnO₂ as raw materials with a suitable stoichiometric ratio. The structural configuration was confirmed by XRD study, and the analysis revealed the structure to be of cubical type. SEM analysis was carried out to get a clear picture of grain and grain boundary. Dielectric and electrical characterization were conducted as a function of temperature as well as frequency ranging from 1kHz to 1 MHz. Complex and modulus spectroscopy analysis were carried out for deep understanding of the material behavior. Broadened dielectric loss peaks were obtained beyond a temperature of 250 °C indicating a non-Debye type relaxation behavior. relaxation peaks were observed at high temperature in a modulus plot, and the activation energies were calculated. The ac conduction phenomenon was found to be thermally activated and the frequency dependence followed Johnscher’s Law. In the present study, a noticeable invariance nature of dielectric constant as well as flat and moderately low loss was observed at moderate temperatures and over a broad range of frequency making the material suitable for wide band application.

Keywords:

• BST
• Dielectric study
• modulus spectroscopy
• ac conductivity