Structure, relaxation behavior and dielectric properties of HfO2 modified Ba (Zr0.2Ti0.8)O3 ceramics synthesized by liquid phase coating method

The z mol% (z = 0, 0.5, 1, 2, 3, 5) HfO2 doped Ba(Zr0.2Ti0.8)O3 ceramics were synthesized by the liquid phase coating method. The HfO2 doped samples exhibit cubic perovskite structure and a pyrochlore phase is formed in the 5 mol% HfO2 doped BZT ceramic due to the substitution of Hf4+ ions for host B site ions. The HfO2 modified Ba(Zr0.2Ti0.8)O3 ceramics possess uniform grain size distribution and the average grain size increases with the increasing HfO2 amount when z <= 1. After increasing z up to 2, the exaggerated grain growth appears in the BZT based ceramics. The dielectric frequency dispersion for Ba(Zr0.2Ti0.8)O3 based ceramics gets enhanced as the HfO2 concentration increases and the almost complete transition diffuseness induced by composition inhomogeneity can be obtained. A comprehensive performance (high epsilon rRT, low tan delta RT and fine Delta epsilon r/epsilon r) is obtained for the 1 mol% HfO2 modified Ba(Zr0.2Ti0.8)O3 ceramic.