Changes in induced anisotropy and magnetostriction in Co-based amorphous alloys

We have carried out isothermal annealings of as-cast and relaxed samples of the amorphous alloy Co70.4Fe4.6Si15B10 in the presence of an in-plane, transverse magnetic field (H=5 kOe) for temperatures 463-598 K. The induced anisotropy Kind as well as the change in the saturation magnetostriction on annealing Δλs was measured as a function of annealing time for comparison with a micromagnetic theory wherein the induced anisotropy results from the thermally activated alignment of mobile atom pairs. For these two quantities, similar two-peaked spectra of activation energies were obtained, corresponding to reversible processes. We conclude that Kind and Δλs are proportional in this alloy. These results are compared to measurements of Kind in Co75Mn2Si14B9. (orig.)