High-Q Li₂Mg₂(MoO₄)₃ dielectrics for LTCC applications at microwave frequencies

Li2Mg2(MoO4)3 dielectric was prepared via the conventional solid-state method, and its dielectric properties were investigated in the microwave frequency region. The XRD patterns of the sintered samples revealed single-phase formation with an orthorhombic structure and a space group belonging to Pnma(62). Lattice parameters, bond length, and Raman spectra of the ceramics were also investigated. The dielectric properties exhibited significant dependence on the sintering conditions. The $${\tau _f}$$ values (resonant frequency temperature coefficient) remained in a range from – 60 to – 69 ppm/°C for all specimens because the changes in the unit cell volume were small. Excellent microwave dielectric properties (εr ~ 9.5, Q × f ~ 80,000 GHz and τf ~ – 69 ppm/°C) can be obtained for Li2Mg2(MoO4)3 ceramics sintered at 880°C for 4 h. This constitutes a very promising material for LTCC applications.