Temperature dependence of electrostriction in rhombohedral Pb(Zn1/3Nb2/3)O3-PbTiO3 single crystals

The temperature dependent electrostrictive behavior of rhombohedral Pb(Zn1/3Nb2/3)O-3-xPbTiO(3) crystals (PZN-PT, x<0.09) was investigated. Although the application of an E field induces a macroscopic ferroelectric phase at room temperature, rhombohedral crystals still exhibit relaxor characteristics, such as polarization modulation. The polarization is believed to become homogeneous in association with the E-field induced phase transition into the tetragonal phase. Electrostrictive coefficients, Q(11)similar to9.5x10(-2) m(4)/C-2 and Q(12)similar to-3.6 m(4)/C-2 were calculated at the high fields. Strain values calculated based upon these coefficients were found to be significantly greater than that measured at low fields, being attributed to polarization modulation. With decreasing temperature, the theoretical strain values came closer to measured strain values. Theoretical and calculated values are expected to be equal at temperatures lower than 150 K, where the polarization in the E-field exposed crystal is homogeneous and collinear. (C) 2002 American Institute of Physics.