Electric-field- and stress-induced R-O phase transformation in [011]-poled Pb(Mg1/3Nb2/3)O3-(28-32)%PbTiO3 single crystals of [100]-length cut

The respective and combined effects of applied electric field and axial compressive stress on the rhombohedral-to-orthorhombic (R-O) phase transformation in d(32) cut [011]-poled PMN-(28-32)%PT single crystals have been investigated. The axial compressive stress in the [100] length direction is found to reduce the R-O transformation field (E-RO) of the crystal. On field or stress removal, PMN-(28-30)%PT reverted back to the rhombohedral state and the original good properties were restored. In contrast, field and/or stress-induced R-O transformation in PMN-32%PT single crystal is irreversible such that the initial properties of the crystal could not be recovered even after field and/or stress removal. The results indicate that while the poled single-domain orthorhombic state is the lowest energy state in PMN-32%PT, multidomain rhombohedral state is the lowest energy state in PMN-(28-30)%PT. The maximum electric-field-induced strains for the linear anhysteretic actuation of PMN-30%PT d(32)-cut crystals under concurrent field and stress condition are determined.