Abstract

Nonlinear magnetic excitations in the Heisenberg magnetic system CsNiF3, when an antiferromagnetic interchain interaction is present between two neighboring easy-plane ferromagnetic chains, are studied. Using a two-lattice model and defining coherent states on each site for the two chains the discrete coupled equation for the averages of the spin components are given. In the easy-plane limit it is found that three kinds of static magnetic excitations can exist, depending on the value of the antiferromagnetic interchain exchange interaction J2. The inclusion of this antiferromagnetic interchain interaction makes the problem of the nonlinear magnetic excitations appear in a new light.