Rod-like grains with high aspect ratio and adjustment of competitive growth of perovskite and tungsten bronze structure in (1−x)Ba(Zr_0.2Ti_0.8)O₃-xBa_0.7Ca_0.3FeTaO₅ ceramics

(1–x)Ba(Zr_0.2Ti_0.8)O₃-xBa_0.7Ca_0.3FeTaO₅ (abbreviated as BXT–x, where x = 0.4, 0.5, 0.8 and 1) ceramics were successfully prepared through a conventional solid-state reaction method. The evolutions of structure and surface morphology with change of the component and the competitive growth of perovskite structure and tungsten bronze structure were investigated. BXT–1 ceramic is composed of rod-like grains with high aspect ratio (20–40) of tungsten bronze structure. Dielectric anomaly accompanied by frequency dispersion was observed in all BXT–x ceramics. We concluded that the dielectric relaxation in the ceramics is derived from electron hopping in the dipole composed of Fe²⁺ and Fe³⁺ and XPS data confirmed the coexistence of Fe²⁺ and Fe³⁺ in the ceramics. Moreover, the sintering atmosphere plays an important role in the competitive growth of perovskite structure and tungsten bronze structure.