Ferroelastic phase transition compositional dependence for solid-solution [(Li0.5Bi0.5)xBi1−x][MoxV1−x]O4 scheelite-structured microwave dielectric ceramics

Abstract

A compositional dependence on the ferroelastic phase transition in scheelite solid-solution [(Li0.5Bi0.5)xBi1−x][MoxV1−x]O4 ceramics was characterized by the microwave dielectric data over the temperature range 10–420K. As x values increased from 0.0 to 0.125, a dielectric temperature-dependent anomaly consistent with a phase transition decreased linearly from 528K for the pure BiVO4 end member to 264K for the solid-solution composition at x=0.125. With further increasing x, the transition temperature decreased sharply to approximately 45K and became stable for x⩾0.52. The phase transition point for pure tetragonal (Li0.5Bi0.5)MoO4 ceramics is approximately 43K. As the x value increases, the Raman band of the [(Li0.5Bi0.5)xBi1−x][MoxV1−x]O4 ceramics at room temperature broadens and overlaps. Ferroelastic domain structures were observed as a function of composition with diffraction contrast imaging and high-resolution imaging with transmission electron microscopy. Structure–property relations are inferred from the microscopy observations and the Raman spectra.