Multilayer Heisenberg models: linear spin wave analysis

The effect of the interlayer and intralayer anisotropies on the energy gap and sublattice magnetization is investigated using the linear spin wave the ory for multilayer Heisenberg models with odd number of coupled layers. In the isotropic case, such systems exhibit a long-range order and no energy g ap, while, in the anisotropic case, they are still ordered and the energy g ap opens for certain anisotropies. (C) 1998 Elsevier Science B.V. All right s reserved.