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 values (resonant frequency temperature coefficient) remained in a range from - 60 to - 69 ppm/degrees C for all specimens because the changes in the unit cell volume were small. Excellent microwave dielectric properties (epsilon(r) similar to 9.5, Q x f similar to 80,000 GHz and tau(f) similar to - 69 ppm/degrees C) can be obtained for Li2Mg2(MoO4)(3) ceramics sintered at 880 degrees C for 4 h. This constitutes a very promising material for LTCC applications.