Revised core-shell domain model for magnetostrictive amorphous wires

The radial, circular, and axial components σ_r, σ_φ, and σ_x, of the residual stress tensor in amorphous wires made by quenching in rotating water are derived from the classical elasticity theory on the assumption that the density decreases from the wire surface (r=r₀) as r⁸ /r₀⁸. After a small reduction in σ_x and a small rotation of the easy directions in the core, the current widely applied core-shell domain model is revised. In contrast to the current model, which assumes an axially magnetized core and different core radius r_c for wires with positive and negative magnetostriction, the revised model assumes: 1) a fixed core radius τ_c~0.75 r₀ and 2) a helical core magnetization tilting about ±30° from the axial (circular) directions for wires of positive (negative) magnetostriction. This revision is consistent with the existing basic results of domain observations and magnetic measurements and it is further supported by experiments using a new technique described in this paper