Influence of A-site Ba substitution on microwave dielectric properties of (Ba_xMg_(1-x))(A_(0.05)Ti_(0.95))O_3 (A=Zr, Sn) ceramics

摘要

The microwave dielectric properties of (Ba_xMg_(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_xMg_(1-x))(Zr_(0.05)Ti_(0.95))TiO_3 (called B_xMZT) 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_xmg_(1-x))(Sn_(0.05)Ti_(0.95))TiO_3 (called B_xMST) ceramics, the dielectric constant increased from 19 to 20.5, Q × f value increased from 120,000 to 37,000 (GHz), and the revalue 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 4h.