BLOCH WALL DYNAMICS IN ULTRATHIN FERROMAGNETIC-FILMS

The domain wall dynamics in 'easy axis' anisotropy films without magne tic loss is considered. Similar to the Walker model of the infinite on e-dimensional domain wall, the dipole-dipole interaction is responsibl e for the presence of a critical velocity in this case. However, its e xperimentally measured value is small compared to Walker's velocity fo r bulk materials. This fact is connected with the effective demagnetiz ation factor reduction when decreasing d - the film thickness. Compari son with the experimental results obtained for ultrathin cobalt films with 'easy axis' anisotropy shows excellent agreement of theory and ex periment. The influence of the relatively weak planar (perpendicular t o the anisotropy axis) magnetic held on the dynamics of the domain wal l and its critical velocity is also analyzed. (C) 1998 Published by El sevier Science B.V. All rights reserved.