Dielectric, conductivity and piezoelectric properties in (0.67-x)BiFeO₃-0.33BaTiO₃-xSrZrO₃ ceramics

A new type of (0.67-x)BiFeO₃-0.33BaTiO₃-xSrZrO₃ (x = 0.00, 0.02, 0.04, 0.06, 0.08 wt%, abbreviated as SZ100x) ternary lead-free relaxation ceramic was prepared by a conventional mixed-oxide sintering method. The surface texture, dielectric, impedance, electrical conductivity and piezoelectric were studied in detail. It was found that three kinds of compounds are completely dissolved into a single structure with a pseudo-cubic (Pc) phase. Besides, scanning electron microscopy figures indicated that proper doping can make the ceramic system more compact while excessive SrZrO₃ content would cause abnormal growth of the grain. In addition, the analysis of dielectric temperature spectra shown that the dielectric peaks gradually widen with an increase in x and the x = 0.04 sample has the strongest relaxation characteristics. Importantly, doping of SrZrO₃ can greatly improve the impendence and electrical insulation characteristics. Besides, high strain value of 0.24% with the normalized strain value of 400 pm/V was obtained at x = 0.04, which was related to the relaxation response of the polar nanoregion under electric field.