MEASUREMENT OF DOMAIN-WALL MOBILITY IN MAGNETOOPTIC MEDIA

Domain wall mobility in magneto-optic (MO) media is important in determining the thermomagnetic recording and erase process. However, measurement of domain wall mobility has been difficult due to the large coercivity of MO media near room temperature and the weak MO signal at high temperature. With an improved high speed polar Kerr MO camera system, the dynamics of domain wall motion can now be imaged and measured at temperatures near T(curie). The domain wall mobility in GdTbFe samples was measured with the bubble collapse method. The experimental results show that the domain wall motion velocity is a linear function of applied bias field and the domain wall mobility is about 0.3 cm/Soe. Samples with different preparation methods are compared and the experiment shows that whereas the dynamic coercivity varies with the preparation method, the mobility is an intrinsic property and dependent primarily upon sample composition.