Shear Strain and Spontaneous Twisting of Ferroelastic Crystals Ba₂NaNb₅O₁₅ and K₂Ba(NO₂)₄

Abstract

Using an inverted torsion pendulum, the peculiarities of low-frequency shear elastic and anelastic properties of the ferroelastic crystals Ba ₂ NaNb ₅ O ₁₅ and K ₂ Ba(NO ₂ ) ₄ have been investigated for various crystallographic oriented samples at temperature variation in the vicinity of their phase transition points. The work gives insight into the nature of the spontaneous shear strain behavior and spontaneous torque arising in the samples at the Curie point.

Keywords:

• Strain
• torque
• twisting
• ferroelastic
• Curie point

Acknowledgment

This work was supported by the Grant of the Russian Federation President for Young Scientists (project No. MK – 7182.2006.2) and RFBR (grant # 06-02-96310).