The effect of mechanical deformation on the magnetic properties of amorphous alloys

Abstract

Amorphous alloys can deform in two distinct modes, one homogeneous and the other inhomogeneous, and it has been known for some time that inhomogeneous deformation produces a severe degradation of soft magnetic properties. We report d.c. measurements on METGLAS^R 2826, VITROVAC^R 0040 and VITROVAC^R 6010 that have been cold rolled up to a 55% thickness reduction. By separately considering the effect of surface roughness on H_c, we are able to give clear evidence for pinning of the domain walls at the bulk shear bands. Measurements on magnetostrictive and non‐magnetostrictive materials provide evidence that the major source of pinning after inhomogeneous deformation is associated with localized stress fields in the sample. As a counterpart to our earlier a.c. measurements on homogeneously deformed ribbon, we report d.c. measurements on samples homogeneously deformed at low strains in a creep rig. H_c in this case remains close to that of a ribbon given the same heat treatment but not crept. The results after deformation in both regimes are discussed in terms of the current models of the effects of deformation.