"Coarse-graining modeling of a moving domain
wall interacting with surface defects"
V. Dobrovitski
Atomic-scale defects can strongly influence the motion of a
domain wall in a ferromagnetic material. Bulk and surface defects
can pin the domain wall, or affect its internal structure
(creating a Bloch line), leading to a drastic changes in the
wall dynamics. Thus, atomic-scale defects control such basic
properties of a ferromagnet as coercive field and the rate of
magnetization reversal.
The interaction of a domain wall, which is a meso-scale entity,
with micro-scale defects is a dynamic nonlinear multiscale
process, for which the standard micromagnetic approach is not
adequate. In the present work, we apply the recently developed
coarse graining approach to model the motion of a domain wall
interacting with surface defects ("surface roughness"). We
present the analysis of the changes in the internal structure of
a moving wall with increasing external field, for different
amplitude and correlation length of the surface roughness. We
also analyze the wall slowdown associated with creation of a
Bloch line.