  The thermal spin-wave distribution in a Ni81Fe19 stripe with an asymmetric
transverse domain wall has been investigated using Brillouin light scattering
microscopy. Clear evidence has been found that the existence of the domain wall
influences the spin-wave distribution of the thermal modes. The thermal
spin-wave modes are quantized due to the confinement in radial direction. They
vanish near the domain wall and a new mode evolves inside this complex domain
wall structure. This effect is attributed to a change of the effective internal
field in the domain wall region. The experimental results agree well with
static and dynamic micromagnetic simulations.
