Influence of geometry on the giant magnetoimpedance of high-aspect ratio amorphous magnetic ribbons

We study the influence of ribbon geometry on the giant magnetoimpedance (GMI) behavior of both low- and high-aspect ratio [length (l)/width (w) = 2–150] ribbons made from commercially available amorphous magnetic materials. Our results indicate that the variation of the ribbons’ GMI with geometry is due to the combination of edge effects (due to damage created by the ribbon cutting process) and global shape anisotropy. In high-aspect ratio ribbons [length (l)/width (w)≥ 20], we find that the GMI decreases with width, which we suggest is due to the cutting process creating induced stresses that suppress the transverse susceptibility at the edge of the material. In lower aspect ratio ribbons [length (l)/width (w) ≤ 20], shape anisotropy results in a relatively rapid increase in GMI with increasing length. We conclude that, with suitable optimization, high-aspect ratio ribbons prepared from commercially available materials are suitable for use as macro-scale sensors that detect small magnetic fields/strains over a large sensing area.