Dynamics of micron size bubbles

Abstract
Dynamic properties of micron diameter bubbles in garnet compositions (EuYb)3(FeGa)5012, (EuTm)3(FeGa)5012, and (Eu)3 (FeGa)5012, are reported here. The coercivities and mobilities of these bubbles compare vary favorably with those of 5–6 micron bubbles. A mobility of 1000 cm/sec/Oe was found for the composition Eu0.8Tm2.2 Fe4.5Ga0.5O12. Despite the fact that Q (the ratio of anisotropy field to the saturation magnetization) is less than 5, these films contain all kinds of soft and hard bubbles, in contrast to what Smith et al. have reported in the case of 5 micron bubbles. However, it was found that when the Q is less than or equal to 2, there exists only one kind of bubble propagating at an angle with respect to the field gradient, in accord with their observation. The micron bubbles with no Bloch lines propagate at a large angle with respect to the direction of the field gradient than 5 micron bubbles, in qualitative agreement with Slonczewski’s theory.