A class of decorated spin- Ising models is introduced which mimics the axial next-nearestneighbor Ising (ANNNI) models. The models are solved exactly in terms of the properties of simple anisotropic Ising models. The phase diagrams in two and three dimensions resemble those for ANNNI models in that they exhibit a multiphase point at which many distinct phases meet. Likewise the local magnetization in each ordered phase is spatially modulated and characterized by a wave vector commensurate with the lattice. In three dimensions bicritical points also occur.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics