Crystal Structure and Microwave dielectric Properties of Ba(Zn _1/3 Ta _2/3 )O ₃ –(Sr,Ba)(Ga _1/2 Ta _1/2 )O ₃ Ceramics

Abstract

The microwave dielectric properties and crystal structure of Ba(Zn 1/3 Ta 2/3 )O 3 – (Sr,Ba)(Ga 1/2 Ta 1/2 )O 3 ceramics were investigated in the present study. The Q value of Ba(Zn 1/3 Ta 2/3 )O 3 was improved by adding 5 mol% Sr(Ga 1/2 Ta 1/2 )O 3 . The maximum Q value of Q × f = 162000 GHz was obtained at 0.95Ba(Zn 1/3 Ta 2/3 )O 3 . 0.05Sr(Ga 1/2 Ta 1/2 )O 3 . For this composition, a lattice super structure caused by hexagonal ordering was observed. A further improvement in the Q value was attained when some Sr was replaced with Ba, and 0.95Ba(Zn 1/3 Ta 2/3 )O 3 · 0.05(Sr 0.25 Ba 0.75 )(Ga 1/2 Ta 1/2 )O 3 exhibited a maximum Q value such that Q × f = 210000 GHz. Despite the increased Q value with the replacement of Sr by Ba, the c/a value, which indicates the degree of lattice distortion, remained constant near image 3/2. The Q value thus improved without lattice distortion in the system Ba(Zn 1/3 Ta 2/3 )O 3 ‐(Sr,Ba)(Ga 1/2 Ta 1/2 )O 3 , whereas the improvement of Q value increased with lattice distortion in the solid solution system with Ba(Zn 1/3 Ta 2/3 )O 3 as an end member.