Relaxor and field-induced strain behavior in lead-free Bi_0.5(Na_0.82 K_0.18)_0.5TiO₃ ceramics modified with BaZrO₃

The crystal structure, microstructure, dielectric, ferroelectric and field-induced strain properties of lead-free (1-x)(Bi_0.5 (Na_0.82K_0.18)_0.5TiO₃)-xBaZrO₃ (x = 0-0.05) ceramics (BNKT-BZ) were investigated. X-ray diffraction analyses revealed that a phase transformation occurred at x = 0.02 from a coexistence of rhombohedral and tetragonal symmetry to another mixed state of pseudocubic and tetragonal symmetry. The temperature and frequency dependence of dielectric constant and loss showed strong frequency dispersive behaviors for all BZ-modified specimens. The polarization and strain hysteresis loops suggested that the addition of BZ signicantly disrupted the ferroelectric order accompanied by an enhancement in field-induced strain up to 0. 26% at x = 0.02.