The Application of the Bethe-Peierls Method to Ferromagnetism

摘要: The method introduced by Bethe and Peierls for treating the problem of order-disorder in alloys is applied to ferromagnetism. first Ising model spin which case treatment much same as it alloy problem, has already been pointed out Peierls. correct used values \textonehalf{} 1 per atom. critical temperatures different types lattices are investigated. gives results agreement with rigorous Bloch spin-wave theory that only three-dimensional found be ferromagnetic. these lie between predicted two Heisenberg approximations. discontinuity specific heat at temperature computed a body-centered lattice spin. magnitude larger than Heisenberg's approximation. 3.4 $3.4k$ atom compares favorably experimental value iron. susceptibility function above point. variation does not obey Curie-Weiss Law but displays some curvature. This curvature explains qualitatively difference "paramagnetic" ferromagnetic also helps remove discrepancy number Bohr magnetons measured high low temperatures.