Estimation of changes in the length of a moving conical domain wall in bistable microwire

Abstract

The single domain wall process of magnetization reversal in a bi-stable microwire is studied. Models for static planar and folded planar domain walls are analyzed. The results obtained show that a folded domain wall can have lower total energy. Based on this finding, the dynamic properties of the more probable conical shape of a moving domain wall were studied. Using a simple model of the folded conical domain wall, the formulas for length, velocity, and mobility of the domain wall as a function of the applied magnetic field were derived. The main result of the proposed model is that it predicts domain wall shortening with an increasing applied magnetic field. Fitting the model function to the experimental data made it possible to estimate the characteristic length of the domain wall and changes in its shape in the magnetic field applied. Comparison of the model and experimental data indicates that there is a difference in eddy current damping for fast and slow domain walls, which may be responsible for the unidirectional effect in domain wall propagation.