Structure instability and high microwave dielectric permittivity of nonstoichiometric (Sr0.4Ce0.4)1-xNdxTi0.8Mg0.2O3 system for wireless communication

Abstract

(Sr0.4Ce0.4)1-xNdxTi0.8Mg0.2O3 [(SC)NdTMgO3, x = 0.1–0.4] non-stoichiometric system were obtained through conventional solid-state synthesis technique. All perovskite peaks were attributed to either single (x ≤ 0.3) and/or mixed (x = 0.4) like phases. A solid solution of cubic structure was obtained for x ≤ 0.2, however, for x ≥ 0.3, the (SC)NdTMgO3 compound, exhibits structure instability and (200)/(310) peaks splitting. The peaks splitting indicates cubic (C-phase) to tetrogonal (T-phase) structure phase transition. All ceramic samples appear nearly dense, presenting a non-uniform grain size distribution. The observed trend of the microwave dielectric properties (εr, τf, Q × f) is mainly related to the formation of structure phase transition, packing fraction, relative density and ionic polarizability. A key microwave (MW) dielectric properties of εr = 53, Q × f = 26,700 GHz and τf = +2.8 pmm/°C could be obtained for composition with x = 0.4.