Interactions between dipole-exchange spin waves in ultrathin antiferromagnetic films

A finite-temperature perturbation formalism is employed to study the nonlinear processes for interactions between the discrete spin waves (SW) in ultrathin antiferromagnetic films, taking account of both dipole-dipole and exchange coupling between the spins. Within a microscopic Hamiltonian approach we obtain the dominant three- and four-magnon interactions at low temperatures, and their contributions to the frequency shift and damping (or reciprocal lifetime) of the discrete SW are evaluated. Numerical results applied to MnF2 are presented