Electric field dependence of piezoelectric properties for rhombohedral 0.955Pb(Zn1/3Nb2/3)O3-0.045PbTiO3 single crystals

The electric field dependence of the piezoelectric properties of rhombohedral 0.955Pb(Zn1/3Nb2/3)O-3-0.045PbTiO(3) crystals were investigated as a function of orientation with respect to the prototypic (cubic) axes. For [111] oriented fields, depolarization and subsequent domain reorientation resulted in an apparent maximum in the piezoelectric coefficients occurring at similar to 5 kV/cm, followed by nonhysteretic d(ij) saturation, indicating a single domain state under bias. By extrapolation, single domain values for the piezoelectric coefficients d(33) and d(31) were determined to be 125 and -35 pC/N, respectively. The hydrostatic piezoelectric coefficient d(h) for single domain crystals was calculated to be similar to 55 pC/N, coincident with the experimentally determined values under hydrostatic pressure. For [001] oriented fields, piezoelectric coefficients d(33[001]) and d(31[001]) as high as 2250 and -1000 pC/N were determined, respectively. Although a high value of d(h[001]) (similar to 250 pC/N) was expected, the experimentally determined value was only similar to 50 pC/N. A change of polar vector within the crystal lattice was discussed in relation to the volume strain associated with an E-field induced phase transition and the possible origin of the discrepancy in hydrostatic d(h) values. (C) 1999 American Institute of Physics. [S0021-8979(99)05705-9].