Stress-induced anisotropy and permeability of magnetostrictive Co-based amorphous alloys

Abstract

Effects of stress-induced uniaxial anisotropy Ku on initial permeability μ of magnetostrictive Co-based amorphous alloys were investigated over a wide frequency region by potting ribbons of the material in epoxy resin. Anisotropy in plane caused the low frequency (kHz) permeability to change as μ∝K−l/2u due to domain wall displacements and, therefore, resulted in large eddy current losses due to wall movements which decreased the permeability in the high frequency (MHz) region. Anisotropy normal to the plane caused the low frequency permeability to change as μ∝K−1u due to magnetization rotation and the permeability in the high frequency region took higher values than for the case of in-planed anisotropy because the eddy current losses were smaller.