Improved dielectric resonator through Nd substitution in SrLa4Ti4O15 ceramics at microwave frequencies.

The effects of neodymium substitution on the sintering temperature and microwave dielectric properties of SrLa 4 Ti 4 O 15 were investigated. A single-phase solid solution with a hexagonal structure was formed in Sr(La 1−x Nd x ) 4 Ti 4 O 15 (x = 0.01–0.1) ceramics. By increasing x from 0.01 to 0.07, the dielectric constant and Q×f value of the sample increased at a sintering temperature of 1590 °C and thereafter decreased. In addition, the increase in the dielectric constant and Q×f value with increasing sintering temperature was in agreement with the increase in density in the composition range of 0.01–0.1. The zero temperature coefficient of resonant frequency of the Sr(La 1−x Nd x ) 4 Ti 4 O 15 (x = 0.01–0.1) ceramics also improved with increasing Nd content. Nd substitution resulted in excellent microwave dielectric properties, obtaining ε r = 47.5, Q×f = 49,900 GHz, and τ f = 0.54 ppm/°C for the x = 0.07 composition. [ABSTRACT FROM AUTHOR]