Stress annealing in Fe_73.5Cu₁Ta₃Si _13.5B₉ amorphous alloy: Induced magnetic anisotropy and variation of the magnetostriction constant

The effect of Joule heating anneals, carried out with the simultaneous application of a mechanical stress (stress-current annealing), on the anisotropy and magnetostriction of Fe_73.5Cu₁Ta₃Si _13.5B₉ amorphous samples is investigated. As a result of these thermal treatments an uniaxial in-plane magnetic anisotropy, characterized by the constant K_σ, was induced in the samples. The dependence of K_σ on the annealing temperature shows a maximum around 450 °C which can be connected to the first stages of the crystallization process. From the measurement of the stress dependence of the magnetization work W_m, the magnetostriction constant λ_s of the as-quenched and thermally treated samples was also evaluated. The results obtained show how the presence of two phases in the partially crystallized material determines the magnetoelastic behavior of these samples.