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a b s t r a c tIn this work, we determine the domain wall velocity in the low field region and study the domain dynamics in as-cast and annealed bi-stable amorphous glass-covered Fe 77.5 Si 7.5 B 15 microwires. In particular, from the relation between the domain wall velocity and magnetic field in the adiabatic regime, the power-law critical exponent b, the critical field H 0 and the domain wall damping Z were obtained. It has been verified that the main source of domain wall damping is the eddy current and spin relaxation, both with a strong relation with the magnetoelastic energy. This energy term is changed by the axial applied stress, which, by its time, modifies the damping mechanisms. It was also verified that the domain wall damping terms present different behavior at low (mainly eddy currents) and high applied stress (spin relaxation).

Magnetic relaxation of CoFeSiB glass-covered microwire under applied stress and Joule heating annealing was investigated by ferromagnetic resonance (FMR) linewidth experiments. We were able to identify the main damping mechanisms and to quantify these damping terms, showing the effect of annealing and applied stress on the damping terms. The study has shown that there are three main damping mechanisms responsible for the FMR linewidth: the Gilbert damping parameter, a damping mechanism due to anisotropy dispersions and two-magnon scattering. The Gilbert damping parameter is constant and not influenced by annealing and stress. The FMR linewidth is very sensitive to anisotropy dispersions and this mechanism has a considerable contribution to magnetic relaxation. The two-magnon scattering is an assignment of the inhomogeneities present in the samples.

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The dynamic properties of the magnetic domain walls in amorphous glass‐covered microwires were studied. The samples was Joule annealed with an alternate current at different frequencies and the dynamic behaviour of the samples were studied at different applied stresses. The Landau–Lifshitz–Gilbert damping parameter and the domain wall mobility have shown that the dynamic response can be improved by increasing the annealing current frequency. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)