Vanishing of energy transport velocity and diffusion constant of electromagnetic waves in disordered magnetic media

The energy transport velocity nu (E) and the diffusion constant D of electromagnetic waves in the presence of randomly distributed ferromagnetic scatterers are studied. nu (E) presents a strong dependence on the relative magnetic permeability mu. and, unlike the nonmagnetic case, exhibits sharp drops in the small-particle limit and never coincides with the phase velocity nu (p). Both nu (E) and D exhibit an oscillatory dependence on mu and vanish for certain values of mu. Since mu. of ferromagnetic scatterers strongly depends on the temperature and applied magnetic field, we suggest that these facts can be explored in technological applications.