High permittivity and low dielectric loss of (1-x) Bi0.5(Na0.48K0.52)0.5TiO3-xBaZrO3 lead-free ceramics

Herein, (1-x)Bi0.5(Na0.48K0.52)0.5TiO3-xBaZrO3 ceramics (aliased as (1-x)BNKT-xBZ, where x = 0.00, 0.03, 0.06, 0.09) were fabricated via solid-state reaction, and the microstructure, dielectric as well as impedance properties were researched in detail. It was found that all the samples exhibited a perovskite structure and few other secondary phase was monitored. With the increase of doped BZ, the mean grain size became lager. Compared with the pure BNT ceramic, the introduction of BZ could effectively optimize the performance of (1-x)BNKT-xBZ ceramics. The dielectric constant could reach 4624, and dielectric loss was as low as 0.0028. Using a modified Curie–Weiss law, the Curie constant, the maximum temperature (Tm), and the diffuseness’ degree were systematically investigated. The behavior of the negative temperature coefficient for this ceramic is observed by impedance spectroscopy, which is similar to that of a semiconductor. Hence, our results indicate that the ceramic can be a promising candidate for high-temperature superconductor applications.