Movement of an individual Bloch wall in a single-crystal picture frame of silicon iron at very low velocities

The movement of an individual Bloch wall in a single-crystal picture frame of silicon iron was studied. By using an electronic apparatus the wall velocity was held constant during the magnetization reversal. It was possible to control the wall velocity down to 10
^-2
mm/s. Even at these low velocities the relationship between the wall velocity
v
and the driving magnetic field
H
is precisely linear:
v = const . (H-H_{0})
. This is to be expected under the given experimental condition
dB/dt = const
.