Spin configurations of the four-sublattice model on rectangular lattice

The spin configurations of the four-sublattice model with seven exchange interaction parameters (four of them are taken as direct-exchange interactions, the other three as super-exchange interactions) on a two-dimensional rectangular lattice have been investigated using a matrix method. For the four sublattices, using the two sets of the exchange parameters, we obtain collinear and non-collinear spin configurations for the given propagation vectors in the ground and the first excited states. When k=0, spin configuration is collinear ferromagnetic mode in the ground state and collinear antiferromagnetic mode in the first excited state. When k=[0.5, 0.5], spin configurations are non-collinear, that is, canted structures. © 2013 Published by Elsevier B.V.