Simulation of dielectric and impedance data using modified Lorentz equation in accordance with experimental data on Ca_0.1Sr_0.9La_xBi_2-xTa₂O₉ ceramics

Abstract

In the present work, ceramic samples Ca_0.1Sr_0.9La_xBi_2-xTa₂O₉ were prepared by solid state double sintering route using AR grade and 99.9% pure reagents. These samples were examined by X-ray diffraction and SEM for phase identification and microstructural investigation. XRD data confirms single phase formation with orthorhombic structure at room temperature. SEM studies revealed randomly oriented needle and plate like morphology, typical to that of polycrystalline nature for higher composition. Dielectric and impedance studies were carried out as a function of temperature at different frequencies. Modified Lorentz equation was used to simulate the temperature dependence of dielectric and impedance data. This equation gives information about the activation energy for thermally orientation of dipoles. The activation energy for thermally orientation of dipoles for the present ceramic samples was found to be in the range 70–100 µeV.

KEYWORDS:

• Ca_0.1Sr_0.9Bi₂Ta₂O₉
• lanthanum doping
• dielectric
• impedance
• modified Lorentz equation