Abstract
We consider the square lattice Heisenberg antiferromagnet with plaquette ring exchange and a finite interlayer coupling leading to a consistent description of the spin-wave excitation spectrum in The values of the in-plane exchange parameters, including ring exchange are obtained consistently by an accurate fit to the experimentally observed in-plane spin-wave dispersion, while the out-of-plane exchange interaction is found from the temperature dependence of the sublattice magnetization at low temperatures. The fitted exchange interactions and give values for the spin stiffness and the Néel temperature in excellent agreement with the experimental data.
- Received 29 April 2002
DOI:https://doi.org/10.1103/PhysRevB.66.100403
©2002 American Physical Society