Domain size effect on the coherent precession mode wall motion in magnetic bubble materials

Abstract

The twist spin angle φ1 in the wall associated with an isolated strip domain is calculated as a function of the strip domain width assuming Schlömann’s trial function φ1 sin[ 1/2 πζ] for wall structure, where ζ is the coordinate normal to film plane normalized with film thickness. The wall motion associated with a strip domain is analyzed as a function of the domain width based on the coherent precession model using the above trial function. It was found that the wall motion changes from the ’’Walker mode’’ to the ’’2π mode’’ through the ’’quasi-π-mode’’ with increasing strip width. The peak velocity decreases slightly from Walker’s critical velocity 2πMγΔ in the quasi-π-mode region, and above this region increases approaching to 2.36πMγΔ with increasing domain width, where M is the saturation magnetization, γ is the gyromagnetic ratio, and Δ is the wall width parameter. These calculations are adapted to the radial motion of the bubble domain wall.