Uniaxial stress dependence of the elastic wave propagation near normal - Incommensurate phase transition in (NH4)2ZnCl4

Authors:

• Zbigniew Tylczyński,
• Bogusław Mróz

Abstract

The effect of uniaxial σ₂ stress on the velocity and attenuation of longitudinal ultrasonic wave propagating along the [001] direction in an (NHO₄)₂ZnCl₄ crystal was studied in the vicinity of the orthorhombic - incommensurate phase transition. A stress induced shift of the transition temperature is dT_I/dσ₂ = 0.2 K/MPa. Application of stress greater that 5 MPa results in the appearance of additional anomalies of velocity and attenuation, which are interpreted as manifestations of a new phase induced by uniaxial stress. © 1997 OPA (Overseas Publishers Association) Amsterdam B.V. Published in The Netherlands under license by Gordon and Breach Science Publishers.