Magnetic domains along shear bands in amorphous metals observed by spin-polarized scanning electron microscopy

Abstract

A novel spin-polarized scanning electron microscope with capabilities of observing microscopic domain structures and determining in-plane magnetization directions has been used to investigate the stress-induced magnetic domains in the Fe78B13Si9 (Allied 2605-S2) metallic glass. The magnetic structure in the vicinity of shear bands that are produced near a Mode III crack has been examined. On the tensile side of bending, arrays of individual, discontinuous magnetic “islands” of similar shape and size (about 2–10 μm in length, 3 μm in width, and spaced about 2–4 μm apart) are uniformly distributed on one side of the shear bands. Their easy axis is about parallel to the shear bands. On the other hand, well-defined elliptical domains are found between shear bands on the compression side of bending. Their easy axes are approximately perpendicular to the shear bands. These results suggest the existence of isolated defects of similar stress fields located along the shear bands. The possibility that these defects are dislocations will be investigated next.