New insight into the thermodynamics of Heisenberg ferromagnets as inferred from high-temperature series
详细信息 查看全文
- 作者：M.D. Kuz'min
- 关键词：Ferromagnetism ; Equation of state ; Landau's theory
- 刊名：Physica B: Condensed Matter
- 出版年：2017
- 出版时间：1 February 2017
- 年：2017
- 卷：506
- 期：Complete
- 页码：48-54
- 全文大小：590 K
- 卷排序：506
文摘
In search of a suitable equation of state for ferromagnets, we revise the information about the Heisenberg model obtainable from high-temperature series. Special attention is paid to the ratio χ3/χ4χ3/χ4 (where χandχ3 are the linear and cubic susceptibilities) related to Landau's quartic coefficient b . It is found in particular that both χ3/χ4χ3/χ4 and b tend to a finite limit as T→TCT→TC. This limit is small — an order of magnitude smaller than predicted by Weiss's molecular field and similar theories — but contrary to the common belief, nonzero. This implies a rejection of the generally accepted critical-point exponents and a return to those of Landau: α=0α=0, β=12, γ=1γ=1, etc.