Ultra-low firing high-k scheelite structures based on [(Li _0.5Bi_0.5)_xBi_1-x][Mo _xV_1-x]O₄ microwave dielectric ceramics

In this work, dense ceramic samples across the solid solution of the [(Li_0.5Bi_0.5)_xBi_1-x][Mo _xV_1-x]O₄ system are prepared using the solid-state reaction process. The monoclinic phase region could be obtained for 0≤x<0.098 and the scheelite tetragonal solid solution region could be obtained for 0.098<x≤1. When x=0.098, the boundary composition [(Li _0.5Bi_0.5)_0.098Bi_0.902][Mo _0.098V_0.902]O₄ could be readily sintered at 650°C and also have excellent microwave properties with a high relative permittivity of 81, and a Q × f value of 8000 GHz and a low temperature coefficient of +9.7 ppm/°C. This ceramic is chemically compatible with both Al and Cu electrode materials at its sintering temperature. It can be an excellent candidate for ultra-low-temperature co-fired ceramic technology and is the highest permittivity microwave material found to date with sintering considerations as low as 650°C.