Observation of Magnetic Domain Structure in Fe₈₁B₁₅Si₄ Amorphous Alloy by Lorentz Microscopy and Electron Holography

Abstract

Effects of heat treatment, with and without an external magnetic field, on the magnetic properties of Fe₈₁B₁₅Si₄ amorphous specimens are investigated by Lorentz microscopy and electron holography. These observations are used to clarify the details of magnetizing processes in the specimens. It is found that heat-treatment with an external magnetic field increases the magnetic anisotropy, while that without reduces the magnetic anisotropy. It is considered that this difference results from the alleviation of the strain field by heat treatment and the induced magnetic anisotropy caused by heat treatment with a magnetic field.