Domain wall mobility in orthoferrite platelets with non-perpendicular magnetocrystalline anisotropy

Domain wall mobility has been investigated in yttrium orthoferrite platelets with different angle α between the c crystal axis and normal to the surface. Depending on the wall orientation with regard to the a crystal axis, the latter in each case located within the platelet plane, skew or normal domain wall was created by the external gradient field /perpendicular or paralel to this axis respectively/. The measurements were carried out using a technique proposed by Shumate. The obtained mobilities for skew and normal walls show a significant difference. The observed effect has been explained on the base of simple theoretical model which predicts the following relation between the skew and normal wall mobilities (μ
s
and μ
n
respectively) depending on the angle
\alpha :\mu_{n} = \mu_{s} \cos \alpha
. The obtained experimental results are in good agreement with this model if only the effective angle α between the wall and normal to the surface has been taken into account, since in experiment the wall was not paralel to the ac crystal plane. A remarkable increase of the dynamic coercivity for the skew wall has been also observed experimentally.