Dynamic hysteresis and scaling behaviours of lead-free 0.94Bi _0.5 Na _0.5 TiO ₃ –0.06BaTiO ₃ bulk ceramics

Bismuth sodium titanate–barium titanate (1 x)Bi _0.5 Na _0.5 TiO ₃ –xBaTiO ₃ (BNT–xBT) ceramics have drawn extensive attention of late as lead-free alternatives to lead zirconate titanate PbZr _1x Ti _x O ₃ (PZT). In this work, the ferroelectric hysteresis loops of a morphotropic phase boundary (MPB) composition of BNT–6BT were measured under electric fields in the frequency range of 0.01 to 10 Hz and fields ranging from 10 to 70 kV cm ¹ . The relaxor ferroelectric BNT–6BT exhibits a three-stage evolution of scaling behaviours between the logarithm of hysteresis area hAi and the logarithm of the amplitude of field E ₀ at medium–high frequencies (herein 0.1 Hz # f # 10 Hz) and two-stage linear scaling behaviours at low frequency (herein f ¼ 0.01 Hz) in the electric field amplitude E ₀ term (10 kV cm ¹ # E ₀ # 70 kV cm ¹ ). The emergence of three-stage and two-stage dynamic hysteresis scaling behaviours in the relaxor ferroelectric BNT–6BT are attributed to the complex couple contributions of 180 and non-180 domain walls. The three-stage and two-stage scaling behaviours are integrated considering the time-dependent domain wall switching processes.