Ferroelectric‐quasiferroelectric‐ergodic relaxor transition and multifunctional electrical properties in Bi _0.5 Na _0.5 TiO ₃ ‐based ceramics

Abstract

Abstract A‐site substituted 0.88(Bi 0.5 Na 0.5 ) 1− x (Li 0.5 Nd 0.5 ) x TiO 3 –0.12BaTiO 3 ( BNTLN x – BT 12) ceramics were synthesized using a conventional solid‐state reaction route. The structural transformation and miscellaneous electrical properties were systematically investigated. The A‐site modification induced two sequence transitions from ferroelectric tetragonal ( T ) to quasi‐ferroelectric pseudocubic ( PC ) phase, followed closely by the second transition from non‐ergodic to ergodic relaxor ( NR ‐ ER ), and finally to dynamic polar nanoregions ( PNR s). The significant enhancement in piezoelectric activity, strain response, broad plateau‐like maximum dielectric permittivity over a large temperature range and energy‐storage level at different compositions may be attributed to the compositionally‐induced T ‐ PC to NR ‐ ER transition and the alignment of dynamically‐fluctuating PNR s, respectively. The evolution of multifunctional electrical properties, associated with the variations in structure/microstructure, might provide a new insight to investigate the underlying mechanism of structure‐electrical properties relationship in ferroelectric solid solutions.