Improvement in Giant Magnetoimpedance by High Ion Dose

The effects of annealing and ion-irradiation on the magnetic properties of amorphous Co
₆₆
Fe
₄
B
₁₅
Si
₁₅
alloys have been investigated by means of the changes of the giant magnetoimpedance (GMI). In general, there are differences in magnitude and shape of the GMI curves between as-quenched amorphous and ion-irradiated samples. The results indicate that the effects of ion irradiation on the magnetic properties of the as-quenched sample are quite large and show the dependence for ion dose. But a drastic decrease and ion-dose dependence, caused by ion-irradiation, is observed in the magnitude of the GMI of the sample annealed at 380°C, which has a maximum value of the GMI due to the presence of ultra-soft magnetic materials.