Sound dispersion in a spin-1 Ising system near the second-order phase transition point

ERDEM R., Keskin M.

PHYSICS LETTERS A, cilt.310, sa.1, ss.74-79, 2003 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 310 Sayı: 1
  • Basım Tarihi: 2003
  • Doi Numarası: 10.1016/s0375-9601(03)00162-2
  • Dergi Adı: PHYSICS LETTERS A
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.74-79
  • Erciyes Üniversitesi Adresli: Evet

Özet

Sound dispersion relation is derived for a spin-1 Ising system and its behaviour near the second-order phase transition point or the critical point is analyzed. The method used is a combination of molecular field approximation and Onsager theory of irreversible thermodynamics. If we assume a linear coupling of sound wave with the order parameter fluctuations in the system, we find that the dispersion which is the relative sound velocity change with frequency behaves as omega(0)epsilon(0), where omega is the sound frequency and a the temperature distance from the critical point. In the ordered region, one also observes a frequency-dependent velocity or dispersion minimum which is shifted from the corresponding attenuation maxima. These phenomena are in good agreement with the calculations of sound velocity in other magnetic systems such as magnetic metals, magnetic insulators, and magnetic semiconductors. (C) 2003 Elsevier Science B.V. All rights reserved.