GIANT MAGNETO-IMPEDANCE AND ITS RELAXATION IN CO-FE-SI-B AMORPHOUS RIBBONS

Systematic measurements of giant magneto-impedance (GMI) and its relax ation (magneto-impedance aftereffect) have been carried out in a serie s of Co-rich amorphous ribbons ranging in magnetostriction values from -3.5 to +3.5 ppm. The value of GMI is a maximum for the alloy with th e lowest value of magnetostriction, corresponding to a maximum of the transverse permeability. The impedance relaxation between two fixed ti mes depends on the magnetostriction constant (lambda(s)) of the sample s, and the observed trend is consistent with the theories which predic t a direct relationship of the conventional permeability aftereffect ( MAE) with the square of lambda(s). Furthermore, the variation of the i mpedance aftereffect with the driving current resembles the behavior o f MAE, and a connection between both effects can be established. (C) 1 997 American Institute of Physics.