Effect of Joule-heating annealing conditions on giant magnetoimpedance of Co-rich amorphous ribbons

Co-rich, soft magnetic amorphous ribbons, with composition Co68.25Fe4.5Si12.25B15 were prepared using a single roller melt-spinning technique. The effect of ac and dc Joule-heating annealing conditions on the GMI of these ribbons was investigated extensively. It was found that not only the current strength and annealing time, but also the cooling conditions, the geometry of the samples and the waveform of the annealing current affected the results significantly. The results of Joule-heating annealing were also found to be reversible under some conditions.