Structural and large electric field-induced bipolar strain study of lead free Bi0.5Na0.5TiO3: Gd piezoceramics

Abstract

In the present work, crystal structure and field-induced bipolar strain response of Pb-free (Bi1-xGdx)0.5Na0.5TiO3 (BNT:Gd) ceramics with x ≤ 0.04 were investigated systematically. Pure perovskite phase exhibited without any notable change in the crystal structure within the range of specimen studied. Structural analysis of BNT: Gd ceramics was performed through Rietveld refinement by Fullprof software. Rhombohedral structure with space group R3c had been confirmed for x ≤ 0.04. Electric field-induced strain showed a butterfly characteristic of bipolar strain hysteresis curve for the composition x ≤ 0.04 in BNT: Gd ceramics at RT. The maximum normalized piezoelectric strain coefficient d∗33 of 148 pm/V was obtained in BNT: Gd systems which is approximately 4.9 times greater than static piezoelectric constant d33 (30pC/N) for the specimen x = 0.04. © 2019 Elsevier Ltd.