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

Abstract

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 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 (k33 > 0:90) and other electromechanical properties of morphotropic PMN-PT single crystals prevail under large drive. The observed k33 roll-off at 42 MPa compressive stress is analyzed in terms of the recent structural data and the high-order Devonshire theory of possible ferroelectricferroelectric transition trajectories.

High performance ferroelectric relaxor-PbTiO3 single crystals: Status and perspective

“…Figure 38. 314 The piezoelectric coefficient d 33 * was found to increase from 1600 to 2500 pC/N with increasing stress, while the coupling factor showed a slight decrease from 0.95 to 0.90, which was also reported by Amin et al [301][302][303][304] The increase in piezoelectric coefficient under compressive stress can be attributed to the stress induced phase boundary motion. As shown in Figure 39, the R-O phase boundary moves to a lower PT region, as a consequence, the rhombohedral crystals approach the R-O phase boundary under stress and give rise to improved piezoelectric properties.…”

“…25 A compressive stress is generally used to prevent the piezoelectric elements from going into tension under high drive field, whereas a dc bias electric field may be applied to stabilize the piezoelectric material and prevent it from depoling. 301,302 In this section, the effect of compressive stress and positive dc bias field on [001] poled relaxor-PT crystals is reviewed, including stress/electric field induced phase transitions and stress/electric field dependence of piezoelectric properties. [33][34][35]70,75,118,119,287,[301][302][303][304][305][306][307][308][309][310][311][312]…”

“…Figure 40 shows the strain behaviors for [001] poled PMN-PT crystals under various levels of uniaxial stress, as reported by Viehland et al [314][315][316][317] It can be observed that the value of strain increased from 2.7 Â 10 À3 to $4.2 Â 10 À3 under a stress of 4 Â 10 7 N/m 2 , indicating that the zero point strain of the crystal is shifted (i.e., a contraction) under mechanical load and the strain can be (partially or fully) recovered with an application of electric field. If the applied uniaxial stress is high enough, the piezoelectric response of [001] poled relaxor-PT crystals will decrease, 301,318,319 owing to the stress induced R-O phase transition and depolarization, as discussed in Sec. V B 1.…”

dc field effect on stability of piezoelectric PZN-0.06PT single crystals under compressive stress

“…First-principles computations 11 The electromechanical properties of PMN-PT single crystals have been investigated under the condition close to naval operation, i.e., large signal response under uniaxial compression. [12][13][14] Furthermore, sound projectors fabricated from PMN-PT and PZN-PT single crystals demonstrated broad-bandwidth, high source level, and size reduction compared to those that use standard lead zirconate-titanate. [15][16][17] In sound projectors that use the 33 length extensional mode, the piezoelectric element is driven by a large electric field ϳ0.4 MV/ m under compressive mechanical stress ranging from 7 to 63 MPa.…”

Achieving single domain relaxor-PT crystals by high temperature poling

“…In addition, compared with the longitudinal piezoelectric response of domain engineered crystals, the shear piezoelectric response of single domain crystals can be used in the condition of high preload stress. Preload stress may induce phase transition and depoling in domain engineered crystals, [22][23][24][25] while the thickness shear mode of single domain crystals was found to be stabilized upon the preload stress. 26 Of particular significance is that the shear piezoelectric coefficient d 24 of single domain orthorhombic crystals was found to maintain similar values at a temperature of −50 °C−100 °C (the T OT phase transition temperature), with the variation being around 6%, 27 while the longitudinal piezoelectric coefficient d 33 of the [001] poled rhombohedral crystals generally exhibits 200-300% variation in the same temperature range.…”