Domain wall dynamics during the devitrification of Fe_73.5CuNb₃Si_11.5B₁₁ magnetic microwires

We have studied the evolution of domain wall dynamics during the devitrification of amorphous and nanocrystalline Fe_73.5Cu₁Nb₃Si_11.5B₁₁ microwires. Depending on the annealing temperature range, three different regimes in the domain wall dynamics can be considered for these materials. Annealing below the Curie temperature, T_c, of the alloy leads to the stabilization of the domain structure and a strong temperature dependence of the domain wall dynamic parameters. However, annealing above T_c leads to a destabilization of domain patterns and a decrease in the domain wall damping in one order of magnitude. Finally, annealing above the crystallization temperature, T_x, leads to the appearance of the nanocrystalline state that is structurally very stable. In this case, the domain wall velocity is very fast due to the lack of magnetic anisotropy and extremely stable with the temperature.