Enhanced relaxation behavior in Bi₂O₃ modified (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ ceramics

Abstract

Lead-free piezoelectric ceramics (Ba_0.85C_0.15−xBi_x)(Zr_0.1Ti_0.90)O₃ system were synthesized by conventional solid-state reaction. The structure, dielectric, ferroelectric and piezoelectric properties have been investigated in detail. X-ray diffraction analysis revealed that all specimens displayed typical perovskite structure at room temperature. Scanning electron microscope results showed that the introduction of Bi element could effectively reduce the sintering temperature and favor grain refinement of BCZT ceramics. Dielectric measurements displayed that a typical relaxor behavior was appeared and dramatically enhanced with Bi concentration, which is mainly owing to the composition fluctuation and structural fluctuation after Bi introduction. The maximum relaxation degree (γ = 1.9326) was obtained with the sample of x = 0.05. The ferroelectric properties combined with current-electric field illustrated that the P–E loops became slimmer and leaner, meanwhile J–E curves gradually changed to be a broad and flat current platform. The variation of ferroelectric behavior was closely related with the emergence of relaxation behavior in (Ba_0.85Ca_0.15−xBi_x)(Zr_0.1Ti_0.9)O₃ ceramics.