Effect of Geometry and Surface Conditions on Giant Magneto Impedance of Amorphous Ribbons

A giant magneto impedance (GMI) effect sensitively depends on DC current annealing. Surface observation of current annealed Fe-based amorphous ribbons was studied using a Nanomagnetics Multimode Atomic Force Microscope (AFM). 2D and 3D AFM images have indicated remarkable surface roughness on the samples. The surface roughness decreases with current annealing. When the material has subjected to an AC current its electrical impedance shows a significant change. In order to understand the geometrical effect, samples were prepared at various width. The measurements for GMI effect have done on as-cast and DC current annealed samples. The current annealing were carried out using the Joule heating technique by passing a DC electric current through the ribbons for 15 min. The AFM measurements have indicated that the current annealing process may cause some structural changes on the material and GMI effect