Influence of A-site Ba substitution on microwave dielectric properties of (BaxMg1−x)(A0.05Ti0.95)O3 (A=Zr, Sn) ceramics

Abstract The microwave dielectric properties of (Ba x Mg 1− x )(A 0.05 Ti 0.95 )TiO 3 (A=Zr, Sn) ceramics were investigated with regard to substitution of Ba for Mg of A-site. The microwave dielectric properties were correlated with the Ba content. With an increase in Ba content from 0.01 to 0.1, the dielectric constant and the τ f value increased, but the Q × f value decreased. The sintered (Ba x Mg 1− x )(Zr 0.05 Ti 0.95 )TiO 3 (called B x MZT) ceramics had a permittivity in the range of 19.1−20.6, quality factor from 180,000 to 25,000 GHz, and variation in temperature coefficient of resonant frequency from −35 to −39 ppm/°C with increasing composition x . For sintered (Ba x Mg 1− x )(Sn 0.05 Ti 0.95 )TiO 3 (called B x MST) ceramics, the dielectric constant increased from 19 to 20.5, Q × f value increased from 120,000 to 37,000 (GHz), and the τ f value increased from −50 to −3.3 ppm/°C as the x increased from 0.01 to 0.1. When A=Sn and x =0.1, (Ba 0.1 Mg 0.9 )(Sn 0.05 Ti 0.95 )TiO 3 ceramics exhibited dielectric constant of 20.5, Q × f value of 37,000 (GHz), and a near-zero τ f value of −3.3 ppm/°C sintered at 1210 °C for 4 h.