The two-dimensional (2D) Heisenberg magnet with a weak easy-plane anisotropy is considered. A renormalization-group analysis in this model is performed for both quantum and classical cases. A crossover from the Heisenberg to 2D (Formula presented) model is discussed. The magnetic transition owing to the interlayer coupling is considered. Analytical results for the Kosterlitz-Thouless and Curie (Néel) temperatures are derived by taking into account two-loop corrections. The results are compared with experimental data, e.g., on (Formula presented) and turn out to provide a quantitative description, unlike the standard one-loop results.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1999|