Packing fraction, bond valence and crystal structure of AVO 4 (A = Eu, Y) microwave dielectric ceramics with low permittivity

The A3+B5+O4 binary oxides have a variety of different structures—monoclinic, and tetragonal—making them suitable candidates for laser hosts, energy storage, microwave dielectric substrates, etc. In this work, we prepared two tetragonal AVO4 (A = Eu, Y) ceramics with zircon structure. The powder X-ray diffraction (XRD) has been used to study phase purity of the zircon-type AVO4 (A = Eu, Y) ceramics. There was a significant correlation between microwave dielectric properties and relative density. Dense EuVO4 and YVO4 ceramics sintered at 1180 °C and 1240 °C exhibited promising microwave dielectric properties with er = 11.6 and 9.9, Q × f = 46,862 GHz and 56,174 GHz, τf = − 49.6 ppm/°C and − 43.7 ppm/°C, respectively. In addition, the relationship between microwave dielectric properties and crystal structure of AVO4 (A = Eu, Y) ceramics were discussed by packing fraction and bond valence theory in detail.