Dynamics of single domain wall propagating in bistable microwire in rapidly-changing magnetic field

The presented experimental method enables study of the dynamics of a domain wall (DW) moving in bistable microwire in a region of rapidly-changing magnetic field. DW velocity versus DW position dependence is obtained in this experiment. Measurements were carried out on Fe 77.5 Si 15 B 7.5 microwire with strong unidirectional effect in DW propagation. The propagating DW is forced to change its parameters in a very short time, which results in the velocity increasing above its equilibrium value after the DW passes the region of rapid increase in magnetic field. In order to interpret the observed experimental behaviour a simple theoretical model was proposed. Comparison of experimental and model dependences produced a high value of DW inertial mass, indicating that the DW area was much larger than the cross-sectional area of the microwire. Another interesting conclusion was that a DW with stronger damping (shorter wall) does not have a lower value of inertial mass.