Excitation Spectrum of Magnetic Domain Walls

The eigenvalue equation for the normal modes of excitation of a moving infinite planar magnetic domain wall in an infinite material having the most general second-rank tensor anisotropy is presented. The eigenvalues and eigenfunctions of both the spin waves in the presence of the moving wall and the excitation of the wall itself are given to first order in velocity. Cylindrical-domain resonance experiments are proposed to test for the existence of the excitation modes and their effect on domain propagation. The dispersion relation for the wall excitation modes is found to imply a new material requirement for high mobility.