NONLINEAR DIPOLE-EXCHANGE SURFACE SPIN WAVES ON FERROMAGNETIC MEDIA

Abstract

Considering the inhomogeneous exchange anisotropy, the nonlinear surface spin waves in a dipole-exchange ferromagnetic media will be investigated. The total free energy of a dipole-exchange ferromagnet (FM) is given, and then the Landau–Lifshitz equation and the boundary conditions for a weakly nonlinear case are derived. The linear and nonlinear dispersion relations for dipole-exchange spin waves are given in a weak nonlinear approximation. The nonlinear Schrödinger equation, for the spin-wave envelope amplitude, is derived and its solitonic solution is discussed.