Synthesis and characterization of temperature stable low-loss (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 (0 ≤ x ≤ 0.1) ceramics for microwave applications

Abstract

In the present work, we prepared (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 (0 ≤ x ≤ 0.1) solid-solutions via traditional solid-state reaction process and investigated their structural, optical, electrical, dielectric, and shielding properties. We report that these (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 compounds experienced structural phase transitions, wherein the tetragonal-structured BaTiO3 (space group P4mm) got transformed to monoclinic-structured Ba4Ti11O26 (space group C12/m1), and triclinic-structured Ba2Ti9O20 (space group P1). Interestingly, the Mg(Ti0.95Sn0.05)O3 showed no structural phase transition and was crystallized in its purest form without secondary phase formation. Additionally, the prepared compositions showed ten Raman active modes, and the relative density of all the samples exceeded 93.5%. The optical bandgap (Egap) values and DC conductivities of the samples were in the range of 3.82 eV–3.92 eV and 9.03 × 10−10 Sm−1–2.55 × 10−9 Sm−1, respectively. The composition 0.925 Mg(Ti0.95Sn0.05)O3–0.075BaTiO3 exhibited the best dielectric properties having relative permittivity (ɛr) of 19.69, loss tangent (tan δ) of 5.1 × 10−3, and temperature coefficient of resonant frequency (τf) of -8.5 ppm/°C at 1 MHz. In the Ku-band (12.4–18 GHz), this composition showed ɛr in the range of 14.62–15.49 and tan δ in the range of 2.85 × 10−2–5.89 × 10−2. An investigation of shielding properties in the Ku-band revealed that the prepared samples delivered average shielding effectiveness in the range of 5.98–6.65 dB. The prepared materials are proposed for microwave applications.