Effect of the ratio of Sr to Ba at A2 sites on the dielectric and ferroelectric properties of tetragonal tungsten bronze Ca 0.4 Sr x Ba 0.6− x Nb 2 O 6 ceramics

Tetragonal tungsten bronze Ca 0.4 Sr x Ba 0.6− x Nb 2 O 6 ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were prepared by a conventional solid-state reaction method. The structural, dielectric, and ferroelectric properties of these ceramics were investigated. The dielectric response varies from normal ferroelectric to relaxor for x > 0.1 while the polarization–electric field hysteresis loop varies greatly for x > 0.4. The corresponding mechanisms are discussed comprehensively. Moreover, since the A1 sites are fully occupied by Ca in the system, the work discloses the effect of the Sr/Ba ratio at A2 sites on dielectric and ferroelectric properties of tetragonal tungsten bronze oxides.