Low-Frequency Shear Elasticity and Mechanical Losses in Ferroelastics

Abstract

The features of acoustic property investigations carried out in different classes of ferroelastic crystals are considered. The special attention is given to elastic and anelastic properties of ferroelastics at low frequencies: the nonlinear hysteretic dependence of a strain on an external mechanical stress, a mechanical relaxation, a spontaneous twisting of samples below a Curie point, etc. Mechanisms of mechanical losses and nonlinear shear elasticity considering a rearrangement of lattice defects and their interactions are discussed.

Keywords:

• Ferroelastic crystal
• internal friction
• shear modulus
• relaxation
• twisting

Acknowledgments

This work was supported by the Russian Foundation for Basic Research (grant # 06-02-96310) and CRDF (project # PG 05-010-1).