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-lead titanate (PMN-PT) single crystals when driven with large fields ∼ 0.4 MV/m (rms) under a combined dc field and mechanical bias similar to those used in the design of sonar. It demonstrates that the remarkable small signal length extensional coupling (k₃₃>0.90) and other electromechanical properties of morphotropic PMN-PT single crystals prevail under large drive. The observed roll-off of k₃₃ at 42 MPa is analyzed within the framework of recent structural data and the high-order Devonshire theory of possible ferroelectric-ferroelectric transition trajectories.