Correlations between the structural characteristics and enhanced microwave dielectric properties of V–modified Li3Mg2NbO6 ceramics

Abstract Novel low-temperature fired Li 3 Mg 2 Nb 1-x V x O 6 (x = 0.02 −0.08) microwave dielectric ceramics were synthetized by the partial substitution of V 5+ ions on the Nb 5+ sites. The effects of V 5+ substitution on structure and microwave dielectric properties were investigated in detail. XRD patterns and Rietveld refinement demonstrated that all of the samples exhibited a single orthorhombic structure. The structural characteristics such as the polarizability, packing fraction and NbO 6 octahedron distortion were determined to establish the correlations between the structure and the microwave dielectric characteristics. The ɛ r values presented a tendency similar to that of the polarizability. The high Q×f values were mainly attributed to the effects of the grain sizes and density rather than the packing fraction. The variation in the τ f values was attributed to NbO 6 octahedron distortion. Notably, the Li 3 Mg 2 Nb 1-x V x O 6 (x = 0.02) ceramics sintered at 900 °C had outstanding microwave dielectric properties: e r = 16, Q×f = 131,000 GHz (9.63 GHz), and τ f = − 26 ppm/°C, making these ceramics promising ultralow loss candidates for low temperature co-fired ceramics (LTCC) applications.