Structural deformation of 0.74Pb(Mg1/3Nb2/3)O3-0.26PbTiO3 single crystal in 1–3 composites due to interface stresses and poling procedure optimization

Abstract

Interface stresses strongly influence the functional property of 1–3 piezoelectric composites. Using the translucent nature of (1 − x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals, we have studied stress distributions and domain configuration changes during poling inside the crystal rods by polarizing light microscopy and piezoresponse force microscopy. It was found that the interface stresses due to interaction with polymeric filler led a deformed rhombohedral phase and caused incomplete poling near rod-edges. Compared with “hard” epoxy (Epotek301) filler, “soft” epoxy (Stycast) filler showed weaker impact on the crystals rods and less influence on domain configurations. We also show that high temperature poling (70 °C) can substantially improve the piezoelectric coefficient of composites filled with hard epoxy due to creeping above the glass transition Tg. Analytic stress distribution equations based on cylinder rods were modified to explain the physical principle and to predict the stress distribution for square rods case, which was verified by finite element simulation to be accurate within 5%.

Increasing Performances of 1–3 Piezocomposite Ultrasonic Transducer by Alternating Current Poling Method

“…It summarizes that a large piezoelectric coefficient ( d ) can increase the sensitivity, and a high electromechanical coupling factor ( k ) contributes to the broad bandwidth [ 11 ]. At present, the piezoelectric materials used in transducers include piezoelectric ceramics, single crystals and composites [ 12 , 13 , 14 ]. Among them, Pb (Zr 1−x Ti x )O 3 (PZT) ceramics and Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) single crystals are the most widely applied in transducers owing to their excellent electromechanical properties and outstanding performance stability [ 15 , 16 ].…”

Alternate current poling and direct current poling for Pb(Mg1/3Nb2/3)O3–PbTiO3single crystals

“…In the last several decades, PMN-xPT SCs in the rhombohedral (R) phase with the PT composition close to the morphotropic phase boundary (MPB: 27 < x < 32) have been studied systematically, since they have ultrahigh piezoelectric coefficients (d 33 > 2000 pC N -1 ) and electromechanical coupling coefficients (k 33 > 0.90) compared with those of the traditional Pb(Zr 1-x Ti x )O 3 ceramics, as many previous studies have reported. [4][5][6][7][8] The large intrinsic (lattice) contribution in domain-engineered configurations instead of the extrinsic domain wall motions observed in ceramic counterparts gives rise to these extraordinary features. 9) A hysteresis-free strain response is also exhibited in relaxor-PT SCs.…”