Influence of A-site Gd doping on the microstructure and dielectric properties of Ba(Zr0.1Ti0.9)O3 ceramics

Pure and Gd-doped barium zirconate titanate (BaZr0.1Ti0.9O3, BZT) ceramics were prepared by solid state reaction method. Phase analysis showed the formation of the pyrochlore phase (Gd2Ti2O7) at about 5 mol% Gd doping in BZT. The microstructural investigation on the sintered ceramics showed that Gd doping significantly reduced the grain size of pure BZT ceramics, from about 100 μm to 2–5 μm. Change in the Gd concentration had minor influence on the grain size and on morphology. An increase in the Gd content decreased the Curie temperature (TC) of the BZT ceramics. The maximum dielectric constant at TC was observed for 2 mol% Gd and with further increase in Gd content the dielectric constant at TC decreased. The dielectric constant was significantly improved compared to that of pure BZT ceramic. Tunable dielectric materials with good dielectric properties can be prepared by doping BZT with Gd.

Research highlights▶ Gd3+ can substitute either A-site or B-site in barium zirconate titanate (BZT). ▶ Solubility limit of Gd3+ at A-site in BZT is less than 5 mol%. ▶ Gd substitution refines the BZT microstructure significantly. ▶ Gd3+ substitution in BZT improves the dielectric properties. ▶ Enhanced dielectric properties could be due to Maxwell–Wagner polarization mechanism.