Single-wall dynamics and power law in bistable magnetic microwires

The dynamics of a single domain wall in finite glass-coated microwires is reported in the low-field regime below the switching field. The power law of the single domain wall propagating over a large distance is confirmed. Three regions are determined for the propagating domain wall. Below some critical field, H0, the domain wall is pinned at the wire's end. Just above that critical field, the wall moves in the adiabatic regime, interacting with the defects during its propagation, with an average velocity of v = S'(H−H0)β. At high field, the domain wall propagates in the viscous regime and its average velocity is proportional to the applied magnetic field, H. An analysis of the temperature dependence of the scaling factor β is further reported. It is also shown that the domain wall mobility parameter S' is field-independent and is proportional to the domain wall mobility S in the viscous regime.