Giant strains of 0.5% accompanying polarization extension and polarization rotation in (Bi0.5Na0.5)TiO3–PbTiO3–Pb(Zn1/3Nb2/3)O3 ternary system

Abstract

Giant electrostrain (* 0.5% @ 7 kV/mm) in a new (0.96 -x)(Bi 0.5 Na 0.5 )TiO 3 -0.04PbTiO 3 -xPb(Zn 1/3 Nb 2/3 )O 3 (BNT-PT-xPZN) ternary system was found to be associated with the evolution of compositionally modulated dielectric relaxation behavior. The x = 0.2 composition with the maximum strain should be in the middle of the ergodic relaxor zone instead of the ergodic-non-ergodic phase boundary. Electric-induced polarization behavior and polarization reversal dynamic scaling behavior as well as in situ synchrotron X-ray diffraction were used to qualitatively and quantitatively analyze the origin of the strain. It is suggested that the main contribution to the strain of the ergodic relaxor dominated compositions, such as x = 0.13 and x = 0.3 near the boundaries of ergodic zone, should be from the electric field-induced polarization extension. However, for the purely ergodic composition of x = 0.2, its strain mainly originates from polarization extension in a low field range and polarization rotation in a high electric field range, taking up 75.6% and 24.4%, respectively.