UNDERSTANDING OF DIELECTRIC PROPERTIES OF Pb_0.2Sr_0.8TiO₃-MgO COMPOSITE FROM NUMERICAL APPROACH

Abstract

Sr 0.8 Pb 0.2 )TiO 3 -MgO composite system has been studied by Somiya et al. At room temperature, attractive relative permittivities (over 100) were obtained with an addition of MgO in (Sr 0.8 Pb 0.2 )TiO 3 . At the same time, low relative dielectric losses, tan(δ), in the range of 10 −4 to 10 −3 were observed in the frequency range from kHz to 4 GHz, respectively. In this study, finite element method with Monte Carlo simulation is conducted for the composition x (Sr 0.8 Pb 0.2 )TiO 3 : (1−x) MgO from x = 0 to 1 in the paraelectric phase (from −50 • C to 200 • C), and the results are computed and compared with the experimental data. The temperature dependence of the relative permittivity of composites was well predicted up to 35.5% volume fraction of (Sr 0.8 Pb 0.2 )TiO 3 . The simulation results show little discrepancy as MgO volume fraction increases. Several possible factors resulting in the differences between experimental results and simulations are discussed.