Effective sound attenuation exponents in magnets

✍ Scribed by A. Pawlak; B. Fechner

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 361 KB
• Volume: 3
• Category: Article
• ISSN: 1862-6351
• DOI: 10.1002/pssc.200562471

✦ Synopsis

Abstract

We try to explain how some magnets belonging to the Heisenberg universality class can be characterised by positive sound attenuation exponents near the critical point. In magnets being also insulators the sound attenuation exponent should be equal to 2__α__ where α is the usual specific‐heat exponent. This exponent is however negative in the Heisenberg universality class. In this paper we interpret the positive attenuation exponents measured in isotropic magnets such as RbMnF~3~, Y~3~Fe~5~O~12~ and Gd~3~Fe~5~O~12~ in terms of the effective critical exponents. The high value of the sound attenuation exponent in anisotropic FeF~2~ can also be interpreted in this way. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)