NEW EQUATIONS FOR DOMAIN-WALL DYNAMICS WITH NONCONSERVATION OF MAGNETIZATION MODULUS

New Slonczewski-type equations taking into account the nonconservation of magnetization modulus are applied to study the steady state motion of a planar domain wall in the presence of an external field normal t o the anisotropy axis. It is shown that calculations of the wall veloc ity in the frames of traditional Landau-Lifshitz-Gilbert equation may lead to essentially the same results in ferromagnets with a wide ferro magnetic resonance line in the case where the relaxation constant in t he Landau-Lifshitz-Gilbert equation is deduced from the domain wall mo bility experimental data, instead of the data on ferromagnetic resonan ce linewidth. (C) 1997 American Institute of Physics.