Domain Wall Dynamics in Low-Loss Garnet Films

Experimental techniques for the study of domain wall motion in bubble materials are discussed. New results are presented concerning the motion of a single plane wall in an epitaxial ($\mathrm{YLa}$ ) ($\mathrm{FeGa}$ ) garnet film with low damping ($\text{α\hspace{0.17em}≈\hspace{0.17em}.01}$ ). The accessible drive field region for linear wall motion is extended by application of an in‐plane field H_yo normal to the wall. Linear wall motion is observed for velocities up to a peak velocity increasing linearly with H_yo. Beyond this region a strong non‐linearity is observed: after a transient with a high wall speed, the velocity falls to a much lower, nearly drive‐field independent value which again increases linearly with H_yo. It is also observed that the dynamic coercive field in the non‐linear mode is 1 Oe higher than in the linear mode. A model of Bloch‐line dominated wall motion may explain the observed phenomena.