Propagation of electromagnetic soliton in antiferromagnetic medium

We study propagation of electromagnetic waves in an antiferromagnetic medium by solving Maxwell equations coupled with a nonlinear spin equation for magnetization of the medium. In the case of isotropic medium, the propagation is governed by perturbed electromagnetic soliton of the perturbed modified Korteweg-de Vries equation. When anisotropy is added as a small correction to the exchange force, we do not observe any qualitative change in the propagation of EMW. However, when anisotropy is treated as a dominant force the propagation is governed by electromagnetic soliton of the derivative nonlinear Schrodinger equation. In both isotropic and anisotropic cases the magnetization of the antiferromagnetic medium is also found to exhibit solitonic behaviour (electromagnetic spin soliton) similar to the propagating electromagnetic soliton. (C) 2002 Published by Elsevier Science B.V.