Piezoelectric Constants Of Crystals Research Articles

Acoustical method for the determination of the elastic and piezoelectric constants of crystals of classes 6mm and 4mm

An acoustical method is proposed for the determination of the elastic and piezoelectric constants of crystals of classes 6mm and 4mm. The method is based on the technique developed for orthorhombic crystals of class mm2 and described in the previous paper [9]. Only three samples are required for the determination of all elastic and piezoelectric constants of crystals belonging to the two symmetry classes of interest; for the crystals of class 6mm, only two samples are necessary. The proposed method can be used only when the signs of the piezoelectric constants are known beforehand. Knowing the sign of electrostriction for the crystals under study, the relative signs of the piezoelectric constants can be uniquely determined in accordance with the data reported earlier [10]. This approach allows one to extend the method used in the previous paper [9] to crystals of classes 6mm and 4mm.

Measurement of piezoelectric constants using an optical heterodyne interferometer

Piezoelectric constants of crystals (SiO2, LiNbO3, LiTaO3) and polymers (PVDF) have been determined by using an optical heterodyne interferometer to measure the strains. With this setup, the minimum detectable displacement is 10−3 Å and the accuracy is 5%. The effect of the bonding to the support has been analysed and experimentally checked. The well established value of the modulus d11 of quartz (2.31 × 10−12 m/V) has been confirmed. For LiNbO3, the controversial value of d33 was determined to be 9.5 × 10−12 m/V.

Homogeneous deformation theory for piezoelectric crystals using the Ewald transformation and relationships among electrostatic contributions to second- and third-order elastic constants.

In order to calculate the electrostatic contributions to the elastic constants of piezoelectric crystals, Fuller and Naimon [Phys. Rev. B. 6, 3609 (1972)] used the conventional method of homogeneous deformation by evaluating the lattice sums using the Ewald transformation and omitting the zero-wave-vector term. This procedure, however, lacks justification, since it is well known that the conventional homogeneous deformation theory breaks down for piezoelectric crystals. We develop here the full theory for this case. (The use of a new technique for performing the theta transformation makes the treatment much simpler.) The theory verifies that the procedure of Fuller and Naimon will give the correct contribution to the elastic constants. We also explain why the zero-wave-vector term remained absent in their treatment. Moreover, we derive for an arbitrary crystal structure some relationships between the electrostatic contributions to the different second- and third-order elastic constants. In view of these relationships, one has to calculate a lesser number of electrostatic contributions for a given crystal structure, and some of the evaluations of Fuller and Naimon become redundant.

Structural aspects of piezoelectricity

Abstract A bond additivity model is proposed which yields a first order approximation for the piezoelectric constants of crystals with complex structures. The application of this model to crystals of the classes 2, 2mm, 32, 3m, 4mm, 6mm, 43m shows good agreement between experimental and theoretical values.

Equations for transforming elastic and piezoelectric constants of crystals

Equations for transforming elastic and piezoelectric constants of crystals

Elastic constants of piezo-electric crystals

Elastic constants of piezo-electric crystals