On the Magnetic Annealing Effect in 2% Cobalt-Copper Alloy I. Induced Ferromagnetic Anisotropy

Abstract

The behavior of ferromagnetic precipitates in copper-cobalt alloy containing ca. 2 wt. % cobalt heat-treated with magnetic field was studied with the object of making clear a physical origin of the induced uniaxial anisotropy observed. The magnitude of magnetic anisotropy induced by magnetic annealing was measured as functions of the aging temperature, aging time, and intensity of magnetic field. It has been found that almost all of the experimental results can be explained by the fine-particle behavior of ferromagnetic precipitates. It is shown that the origin of magnetic annealing can be explained neither by the magneto-elastic anisotropy of directional deformation nor by the magnetocrystalline anisotropy, but by the shape anisotropy of precipitated particles, which is distributed preferentially along the direction of magnetic field applied during annealing. It is also shown that the magnetic annealing affects remarkably the initial precipitation process rather than the over-growth stage of precipitation.