GMI measurements in ribbons of Co70.4Fe4.6Si15B10 in a wide range of frequencies

This paper reports room-temperature giant magnetoimpedance (GMI) data, meas ured in samples made of pieces of ribbons of amorphous Co70.4Fe4.6Si15B10 i n the microwave frequency range (f = 2-12 GHz), for magnetic fields H up to 0.2 T. The measurements were carried out using the samples as one of the c onductors of a microstrip line terminated by a short and connected to a net work analyzer. We found that values of H. corresponding to the position of the peaks in the impedance spectrum and the peak widths, increase with f. B oth the f- and H-dependence of the GMI are in good agreement with a theoret ical model based on the dynamics of the domain wails at low f and on the fe rromagnetic resonance at high f. (C) 2001 Elsevier Science B.V. All rights reserved.