“…The barred quantities denote the remote loadings, such as E i denote the applied electric field, and r ij the applied stress field (i, j = 1, 2, 3). The spontaneous strain (c À a)/a = 0.01, the spontaneous polarization intensity P s = 0.26 C/m 2 , the dielectric constant e = 1900e 0 = 1.68 · 10 À8 F/m (Jaffe et al, 1971), the coherent domain wall energy C coh = 0.002 J/m 2 (Lines and Glass, 1979), the grain size D = 15 lm (Kolleck et al, 2000), and the function f ðV 90 Þ ¼ P 1 k¼1 sin 2 ðV 90 kpÞ=k 3 (Yang et al, 2001b).…”