Stress and/or field annealing of Fe73.5Cu1Nb3Si15.5B7 amorphous ribbon

The magnetic anisotropy induced by stress (500 MPa) and/or axial magnetic f ield (750 Aim) annealing in Fe73.5Cu1Nb3Si15.5B7 amorphous alloy has been i nvestigated. The thermal treatments were carried out using the current anne aling technique (current densities ranging from 30 to 47 A/mm(2), duration of 120 s). A uniaxial in-plane magnetic anisotropy was induced in the sampl es as a result of these thermal treatments. The easy axis of this induced a nisotropy at current densities < 40 A/mm(2) was transverse (stress annealin g (SA) and stress + field annealing (SFA)) or longitudinal (field annealing (FA)) to the ribbon direction. At current densities > 40 A/mm(2) the easy axis is parallel to the axis of the ribbon for the three types of treatment . The dependence of this induced anisotropy on the current density has a ma ximum (1000 J/m(3)) around 40 A/mm(2), which we relate to the first stages of the crystallization process followed by a minimum at around 47 A/mm(2). Similar dependence was obtained for the coercivity of the samples after the se thermal treatments. A coercivity of about I Aim has been achieved after magnetic FA. (C) 2001 Elsevier Science B.V. All rights reserved.