Kinetics of changes in initial permeability produced by magnetic annealing in a zero-magnetostrictive FeCoSiB amorphous alloy

Abstract

The kinetics of the changes in initial permeability μ produced by magnetic, parallel, and perpendicular field annealing have been measured in a zero-magnetostrictive Fe4.7Co70.3Si15B10 amorphous alloy in the temperature range 320–700 K. The activation energy obtained from μ−1 data is equal to 2.05 eV and is the same as one obtained from direct anisotropy measurements. However, the activation energy obtained from the kinetics of permeability itself is much smaller, in the range 1.05–1.5 eV, and the discrepancy among the published values is explained. There is a proportionality between the μ−1 value and the amount of induced anisotropy, and the proportionality factor depends on the direction of Ku.