Hexagonal Piezoelectric Crystal Research Articles

Shear Surface Acoustic Waves in Twinned Piezoelectric Crystals of the $$\bar {6}$$m2 Symmetry Class

Shear surface acoustic waves, whose existence is due to the difference in the signs of piezoelectric modulus tensors of adjoining halves of crystal, are studied on flat interfaces of twinned hexagonal piezoelectric crystals of the $$\bar {6}$$m2 symmetry class. In this case, the inversion axis $$\bar {6}$$ is perpendicular to the interface between the halves. It is shown that, at a weak piezoelectric effect, the characteristic penetration depth of these waves is inversely proportional to the square of component e222 and may significantly exceed the length of the surface wave.

Acoustic wave tunneling in a gap between hexagonal piezoelectric crystals with relative longitudinal displacement

The influence of relative longitudinal displacements of two hexagonal piezoelectric crystals on the refraction of acoustic waves in the gap between these crystals is considered.

Ring waveguide resonator on surface acoustic waves

A simple regular electrode structure for surface acoustic wave (SAW) devices is proposed. The structure consists of an interdigital transducer in the form of a ring placed on the Z cut of a hexagonal piezoelectric crystal. Finite thickness electrodes produce the known slowing effect for a SAW in comparison with this SAW on a free surface. The closed “slow” electrode region with the “fast” surrounding region forms an open waveguide resonator structure with the acoustic field concentrated in the electrode region. If the radius of the structure is large enough for a given wavelength, an acceptable level of radiation losses can be reached. The electrical admittance of such resonator does not have sidelobes.

Moving dislocations in general anisotropic piezoelectric solids

AbstractThe explicit closed‐form solution is presented for a moving dislocation with the generalized Burgers vector $ {\bf {\tilde b} } $ = [b1, b2, b3, Δφ]T in an anisotropic piezoelectric solid, where Δφ corresponds to an electric dipole layer along the slip plane. The steady‐state version of the Stroh formalism for piezoelectricity is used in this work. Particular attention is paid to the basic characteristics of the electric displacement and electric field due to the moving piezoelectric dislocations. As an important example, a detailed analysis is made for moving dislocations in hexagonal piezoelectric crystals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Moving antiplane shear crack in hexagonal piezoelectric crystals

Closed-form solutions are obtained and discussed for the stress and electric displacement fields around a loaded Griffith-type antiplane shear strip crack moving in hexagonal piezoelectric crystals. Representative numerical results are presented for ZnO and PZT-4.

Antiplane shear crack in hexagonal piezoelectric crystals

General closed-form solutions are obtained and discussed for the stress and electric displacement fields around a mechanically and electrically loaded Griffith-type antiplane shear strip crack in hexagonal piezoelectric crystals.

Two-phase potentials in the analysis of smart composites having piezoelectrical components

Abstract The piezoelectric smart composite material consisting of two discrete phases of hexagonal piezoelectric crystals is subjected to mechanical and electric loads causing out-of-plane displacement and in-plane electric field. The two-phase potential method is introduced to linear piezoelectricity and worked out for the case of the antiplane deformation of a piezoelectric composite. It is shown that only two holomorphic functions (two-phase potentials) are sufficient to fully describe the field variables of the corresponding piezoelectric problem. The power of the method is exhibited by finding the two-phase potential solution to several piezoelectric problems of micromechanics of smart composites.

Finite-Element Analysis of Periodic Waveguides for Acoustic Waves

A numerical approach based on the finite-element method is described for the analysis of periodic waveguides for acoustic waves. The validity of the method is confirmed by comparing the numerical results for the dispersion curves of horizontal shear (SH) surface wave propagation along a corrugated surface of an isotropic material with the experimental results. We also demonstrate the application of this approach by investigating the propagation characteristics of SH surface waves on corrugated layered surfaces of isotropic materials and of SH surface waves propagating under a metallic grating on a surface of a hexagonal piezoelectric crystal.

Propagation of elastic waves in hexagonal piezoelastic crystals

The propagation of elastic waves in an arbitrary direction through a hexagonal piezoelectric crystal is investigated. Orientational relations are obtained in analytic form for the effective elastic moduli and the piezoelectric and dielectric constants, and also for the basic parameters of the elastic waves: the phase velocity, electromechanical coefficient, and the divergence between the displacement vector and the energy flux. Expressions are given for the directions in which the electromechanical coefficient takes an extremal value, and the basic parameters are calculated for cadmium sulfide.

Dispersion of Surface Elastic Waves Produced by a Conducting Grating on a Piezoelectric Crystal

The dispersion relation for surface elastic waves propagating under a thin metallic grating on the basal plane of a hexagonal piezoelectric crystal is investigated theoretically. Purely reactive loads are assumed connected between adjacent electrodes of the grating. The effect of mass loading due to the grating is neglected. The presence of the grating imposes periodic boundary conditions on the piezoelectric fields associated with the surface wave. The resulting boundary-condition problem is solved to obtain the dispersion relation for surface elastic waves. For a material with a large electromechanical coupling coefficient an inductance connected between adjacent electrodes can cause a large reduction in the phase velocity of the surface wave. (For example, in PZT-4, this reduction is about 10%.)

Propagation of Piezoelectric and Elastic Surface Waves on the Basal Plane of Hexagonal Piezoelectric Crystals

Propagation of piezoelectric and elastic surface waves on the basal plane of hexagonal piezoelectric crystals has been investigated theoretically. Variations of the piezoelectric field and the particle displacement with the distance from the surface have been derived and compared with Stoneley's result for nonpiezoelectric crystals. The results are applied to hexagonal CdSe, CdS, and ZnO. For CdSe and CdS, the surface waves are pure Rayleigh modes. However, for ZnO which has relatively large piezoelectric coupling coefficients, the surface waves are found to have the form of a general surface wave defined by Synge. Velocities of surface waves propagating on the basal plane of CdSe, CdS, and ZnO are computed to be 1.470×105, 1.7306×105, and 2.70×105 cm/sec, respectively, which are in good agreement with measured values.