Velocity dependence of magnetic domain wall damping

Measurements of the radial motion of an isolated magnetic bubble domain in epitaxial garnet films in response to short duration magnetic field pulses have been made over a wide range of field pulse amplitudes in a high-g film and two normal-g films, one of which was ion implanted. A least squares fit of the data to the Walker model yielded values of the effective damping parameter considerably larger than the FMR value, except in the high-g film at low velocities. Comparison of the data with the Bloch line and spin wave models of wall motion indicates that these models are inadequate to explain the observed effects.