Piezoelectric and ferroelectric properties of <001>c Pb(In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals under combined thermal and mechanical loading

The direct piezoelectric coefficient and permittivity of < 001 > c-0.26Pb(In1/2Nb1/2)O-3-0.47Pb(Mg1/3Nb2/3) O-3-0.27PbTiO(3) (PIN-PMN-PT) single crystals were simultaneously measured as functions of temperature and uniaxial compressive stress at various frequencies. The results show a nonlinear increase of the piezoelectric coefficient from similar to 1300 pC/N at 25 degrees C to over 8000 pC/N at 99 degrees C, followed by a sharp decrease and gradual decay to zero. The peak in piezoelectric coefficient coincides with a dielectric anomaly that is associated with a rhombohedral to tetragonal phase transition. An increase of the compressive bias stress reduced the magnitude of the peak in piezoelectric coefficient and shifted it to lower temperatures, revealing an initial increase in the piezoelectric response understood to be due to a stress-induced phase transition. The large-signal macroscopic constitutive behavior was characterized at various compressive stresses from 25 degrees C to 150 degrees C. These data are contrasted with the small-signal piezoelectric measurements and show the combined influence of stress and temperature on the electromechanical properties and stress-induced phase transitions in relaxor ferroelectric PIN-PMN-PT single crystals. Implications of the results for the application window of single-crystal PIN-PMN-PT transducers are discussed. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.