A Lumped-Constant Model of Vertical Bloch Lines

Abstract

A formulation has been developed in which the magnetization structure along a magnetic domain wall within a vertical Bloch line is regarded as packed into a single point on the wall, concentrated Bloch-line point. Equations of motion have been derived for the concentrated Bloch line from equations of wall motion developed previously for a two-dimensional wall which was regarded as a locus of domain-center points. Programs have been developed to solve the motion of a domain wall which is arbitrary in shape and contains arbitrary number of concentrated Bloch lines. The results of computer simulation made for bubbles and plane-like walls show the validity of the formulation and the numerical method. The new equations of motion for concentrated Bloch line have been found not to be as stiff as the conventional equations of wall motion in the case with Bloch lines. An outline of the formulation and the method of numerical solution are presented together with preliminary results of computer simulation.