Low temperature sintering and dielectric properties of LaAlO₃–BaSnO₃-based microwave dielectrics

LaAlO₃–BaSnO₃ ceramics as a new microwave dielectric material were investigated in terms of optimum synthesis conditions and thereby the relative density, microstructure, solid-solution state, and dielectric properties with the addition of various sintering aids at different sintering temperatures. The dielectric properties of 0.9LaAlO₃–0.1BaSnO₃ (LA-0.1BS) were strongly influenced by relative density, microstructure, chemical ordering, and mixing rule of the dielectric constant. Densification of the LA-0.1BS ceramics was improved from 82.3 to 96.13% with an average grain size of around 1.9 µm at reduced sintering temperature by 250°C. The LA-0.1BS ceramics sintered with 3 mol% of Bi₂O₃–SiO₂ (BS) showed dielectric constant (ϵ_r) ∼21.18 with associated dielectric loss (tan δ) ∼0.00824 and Q × f ∼1213.59 (10 GHz) which could be achieved at low sintering temperature of 1400–1450°C.