The Baric Changes of the Electron Polarisability of LiRbSO₄, LiKSO₄ and (NH₄)₂BeF₄ Crystals

Abstract

The effect of uniaxial mechanical stresses on the spectral and temperature dependences of principal refractive indices n _i and birefringence Δ n _i of LiRbSO₄, LiKSO₄ and (NH₄)₂BeF₄ crystals have been studied in the wide spectral (250–800 nm) and temperature (100–800 K) ranges. Displacements of the PT points under the uniaxial stress action as well as both an extensition or narrowing of the temperature intervals of the incommensurate phase have been revealed. The baric increacement of the n _i was observed.

Keywords:

• Refractive indices
• birefringence
• phase transition
• incommensurate phase
• uniaxial mechanical stresses

PACS numbers:

• 78.20. Ci
• 78.20. Hp
• 78.20 Wm.