中国物理B ›› 1995, Vol. 4 ›› Issue (7): 542-549.doi: 10.1088/1004-423X/4/7/009

• • 上一篇    

SPECIFIC HEAT OF A HEISENBERG SYSTEM WITH FINITE SIZE

蒲富恪1, 孙继荣2, 魏玉年2   

  1. (1)also Chinese Center of Advanced Science and Technology (CCAST) (World Laboratory), Beijing 100080, China.; (2)State Key Laboratory for Magnetism, Institute of Physics, Academia Sinica, Beijing 100080, China
  • 收稿日期:1994-10-18 出版日期:1995-07-20 发布日期:1995-07-20
  • 基金资助:
    Project supported by the National Scaling Project of Nanocrystal Materials of China.

SPECIFIC HEAT OF A HEISENBERG SYSTEM WITH FINITE SIZE

SUN JI-RONG(孙继荣), WEI YU-NIAN (魏玉年), PU FU-CHO (蒲富恪)   

  1. State Key Laboratory for Magnetism, Institute of Physics, Academia Sinica, Beijing 100080, China
  • Received:1994-10-18 Online:1995-07-20 Published:1995-07-20
  • Supported by:
    Project supported by the National Scaling Project of Nanocrystal Materials of China.

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摘要： Based upon the spin wave theory, the influence of the size of a three-dimensional Heisenberg system on its thermodynamic properties was studied. It is found that the specific heat increases due to the finite size and free surface of the system. For a magnetic film with finite thickness, the interaction of spin waves was also discussed. There exist three additional scattering processes, namely, the scattering between spin waves with wave-vectors parallel to the surface of the film (two-dimensional spin wave), the scattering between two and three-dimensional waves, and the scattering between those waves with the same component in the direction along the thickness of the film. As a result, the T4 term, arising from the coupling of spin waves, in the expression of the specific heat of the system, splite into three parts proportional to T5/2,T7/2 and T4, respectively. Here T is the temperature.

Abstract: Based upon the spin wave theory, the influence of the size of a three-dimensional Heisenberg system on its thermodynamic properties was studied. It is found that the specific heat increases due to the finite size and free surface of the system. For a magnetic film with finite thickness, the interaction of spin waves was also discussed. There exist three additional scattering processes, namely, the scattering between spin waves with wave-vectors parallel to the surface of the film (two-dimensional spin wave), the scattering between two and three-dimensional waves, and the scattering between those waves with the same component in the direction along the thickness of the film. As a result, the T4 term, arising from the coupling of spin waves, in the expression of the specific heat of the system, splite into three parts proportional to T5/2,T7/2 and T4, respectively. Here T is the temperature.

中图分类号:  (Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.))

  • 75.40.Cx
75.70.Ak (Magnetic properties of monolayers and thin films) 75.30.Ds (Spin waves) 75.10.Jm (Quantized spin models, including quantum spin frustration)