An empirical relation for the saturation velocity in bubble domain garnet materials

An empirical relation is given for the saturation velocity of a domain wall in a bubble domain garnet material. The relation is
v_{o3} = 0.4\pi\gammaM(A/K_{u})^{1/2}
, where
V_{o3}
is the saturation velocity, γ the gyromagnetic ratio,
4\piM
the saturation magnetization, A the exchange constant and K
u
the uniaxial anisotropy constant. The relation provides a close approximation for a wide range of experimental data. Comparisons between experimental data and theoretical data are made. A possible interpretation of the empirical relation is given.