Electromechanical properties of high coupling single crystals under large electric drive and uniaxial compression

This work investigates the 33-mode electromechanical response of relaxor-ferroelectric lead magnesium niobate-titanate (PMN-PT) single crystals when driven with large fields /spl sim/0.4 MV/m under a combined direct current (DC) field and mechanical bias similar to those used in the design of sound projectors. It demonstrates that the remarkable small signal length extensional coupling (k/sub 33/ > 90) and other electromechanical properties morphotropic PMN-PT single crystals prevail under large drive. The observed k/sub 33/ roll-off at 42 MPa compressive stress is analyzed in terms of the recent structural data arid the high-order Devonshire theory of possible ferroelectric-ferroelectric transition trajectories.