Cation distribution of high-performance Mn-substituted ZnGa2O4 microwave dielectric ceramics

In current study, only 5 mol% Mn2+ was applied to fabricate high performance microwave dielectric ZnGa2O4 ceramics, via a traditional solid state method. The crystal structure, cation distribution and microwave dielectric properties of as-fabricated Mn-substituted ZnGa2O4 ceramics were systematically investigated. Mn2+-substitution led to a continuous lattice expansion. Raman, EPR and crystal structure refinement analysis suggest that Mn2+ preferentially occupies the tetrahedral site and the compounds stay normal-spinel structure. The experimental and theoretical dielectric constant of Zn1-xMnxGa2O4 ceramics fit well. In all, this magnetic ion, Mn2+, could effectively adjust the τf value to near zero and double the quality factor from 85,824 GHz to 181,000 GHz of Zn1-xMnxGa2O4 ceramics at the meantime. Zn1-xMnxGa2O4 (x = 0.05) ceramics sintered at 1400 °C for 2 h exhibited excellent microwave dielectric properties, with εr = 9.7(@9.85 GHz), Q × f = 181,000 GHz, tanδ = 5.44 × 10−5,and τf = − 12 ppm/°C.