Experimental and theoretical correlation between low-field power absorption and magnetoimpedance in amorphous materials

We present measurements of low-field power absorption (LFA) at 9.45 GHz on an amorphous ribbon of nominal composition (Fe0.06Co0.94)(75)Si15B10), at room temperature. These results show an anti-symmetrical shape around zero magnetic field that peaks at +/- 34 Oe. We also present measurements of magnetoimpedance (MI) at 60 MHz and 3 GHz. In order to make a proper comparison between these experiments, the real part of magnetoimpedance, Re(Z(s)), was numerically derived to obtain dRe(Z(s))/dH; leading also to an anti-symmetrical plot that peaks at the same fields that LFA. By using the complex Poynting vector, we show that LFA and MI are very similar processes and conclude that both measurements are a manifestation of the same response to electromagnetic absorption, in which the same physical processes take place. (c) 2007 Elsevier B.V. All rights reserved.