Effects of Zn non-stoichiometry on the phase evolution and microwave dielectric properties of Li2Zn1−xGe3O8 (0 ≤ x ≤ 0.2) spinels

Abstract

A series of Li2Zn1−x Ge3O8 (0 ≤ x ≤ 0.2) spinels were prepared by the conventional solid-state reaction. The phase composition and microstructure were investigated using X-ray diffraction, Raman spectroscopy and scanning electron microscope. The microwave dielectric properties of samples were observed strongly dependent on the sintering temperature and composition. Li2Zn1−x Ge3O8 (0 ≤ x ≤ 0.2) ceramics were well densified at 950 °C for 4 h and the best microwave dielectric properties were achieved at x = 0.15 with e r = 8.7, Q × f = 99,600 GHz (at 15.0 GHz), and τ f = −60.1 ppm/°C. Furthermore, the chemical compatibility with the silver electrode were confirmed for Li2Zn1−x Ge3O8 ceramics. These ceramics could be possible candidates as LTCC materials.