Critical sound propagation in MnF2

✍ Scribed by A. Pawlak

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 244 KB
• Volume: 3
• Category: Article
• ISSN: 1862-6351
• DOI: 10.1002/pssc.200562470

✦ Synopsis

Abstract

We analyse the critical sound attenuation in the antiferromagnet MnF~2~ above its Neel temperature. A general formula for the acoustic self‐energy, derived in the model in which a sound mode is coupled to both the order‐parameter fluctuations as well as to the energy mode, is applied to interpret the experimental data in MnF~2~. It has been shown that a very interesting competition between three asymptotic singularities is responsible for the complex behaviour of the sound attenuation coefficient in the high‐temperature phase. The relative strength of these terms depends also on the ultrasonic frequency. For high frequency sound propagation also a background attenuation starts playing an important role. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)