Electric field induced anisotropy in electrostrictive Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃crystals

Abstract

The electrostrictive behavior in single crystals of Pb(MglpNb2/3)03 (PMN) and 0.93Pb(Mg1!3 NbZ/3)03 -0.07PbTi03(PMN-7%PT) was investigated as a function of crystallographic direction. The pseudocubic nature of these materials became highly anisotropic at relatively high electric fields. The observed anisotropy was believed to be associated with an electric field induced rhombohedra1 symmetry. Strain values were found to be larger for (001 ) oriented crystals though larger polarization values were measured in (1 11) oriented crystals, a consequence of larger electrostrictive coefficients (Q,). The electrostrictive coefficient Q, of the induced phase was found to be independent of composition. Though the crystals exhibited a high degree of anisotropy, no apparent improvement in induced polarization or strain was found when compared with polycrystalline counterparts.

Origin of the High Piezoelectric Response inPbZr1−xTixOGuo1, Cross2, Park3 et al. 2000Phys. Rev. Lett.1,032345464View full textAdd to dashboardCite

“…4, ∆d/d is plotted versus the applied field, E, for the (200) It is interesting to compare in Fig.4 the results of dilatometric measurements of the macroscopic linear elongation (∆l/l) on the same pellet, which must also reflect the effects of domain reorientation. At higher fields, this contribution diminishes and one could expect the ∆l/l vs. E curve to fall off between those for the [100] and [111] oriented grains, typical of the strain behaviour of polycrystalline ceramics [15]. Although such a trend is seen above 30 kV/cm, it is intriguing to note that below this value, the macroscopic behavior is essentially the same as the microscopic behavior for the (200) reflection.…”

High‐Strain Lead‐free Antiferroelectric Electrostrictors

“…These results were compared with KNN-doped BNT-BT of compositions (1-x)[0.94Bi 0.5 Na 0.5 TiO 3 -0. [16] (data available only for right branch) and PMN-7PT [14].…”

“…The electrostrictive strains of the antiferroelectric (BNT-BT-18KNN) at room temperature and at 150 8C are compared in Figure 5 and Table 1 with lead-containing (PMN-7PT) [14] and lead-free ferroelectric relaxors (Sr 0.35 Na 0.25-Bi 0.35 TiO 3 or SBNT). [7] As can be seen from Figure 5, the BNT-BT-18KNN material at room temperature reaches the highest strains (Fig.…”

“…[13] One way to circumvent the remanent strain problem is to use electrostrictive actuators. While lead-containing electrostrictive materials based on relaxor ferroelectrics have seen a large interest at temperatures above the permittivity maximum, [14,15] there were only few reports on lead-free relaxor ferroelectrics. [7] A big drawback of this approach based on relaxor electrostrictors lies in the fact, that, according to Equation 3, a large strain is achieved only if the maximum polarization remains large throughout the application regime.…”

High dielectric tunability, electrostriction strain and electrocaloric strength at a tricritical point of tetragonal, rhombohedral and pseudocubic phases

“…It is known that the electrostricitve strain follows the theoretically derived quadratic relation [30,34,35]:…”