Four-sublattice model of a biaxial antiferromagnet and its comparison with experiment
Abstract
Utilizing a four-sublattice model that takes account of the Dzyaloshinskii interaction and the tensor nature of the g-factor for spectroscopic splitting, we consider the ground states and frequency–field dependences of the antiferromagnetic resonance of a biaxial antiferromagnet at T = 0 in a magnetic field parallel to the “easy” antiferromagnetism axis. It is shown that the effect of the Dzyaloshinskii interaction and the anisotropy of the g-factor may be reduced to a renormalization of the frequency–field dependences of the antiferromagnetic resonance parameters of the two-sublattice model only for the case of small fields. Expressions are obtained that make possible a self-consistent determination of the phenomenological parameters of the four-sublattice model through the use of experimental antiferromagnetic resonance data. An analysis of experimental microwave and IR absorption data is carried out in terms of the proposed model for the case of the antiferromagnet CuCl2 · 2H2O.