High-frequency magnetoresonance absorption in amorphous magnetic microwires

Abstract

The Fe69Si16B10C5, Co75Si10B15, Co68Mn7Si10B15 amorphous microwires have been studied by the magnetoresonance absorption technique in the X (9.5 GHz), K (20-27 GHz) and Q (30-37 GHz) frequency bands. The specimens under study were metal threads of about 5 mum in diameter coated with dielectric Pyrex layer with thickness 5 mum. The dependences of magnetic resonance spectra on frequency and wire orientation have been measured. The analysis of the resonance signal parameters has revealed that well-known classical equations for FMR in a cylindrical-shaped sample could not be applied for these microwires. It is shown that due to the skin depth effect the model of hollow cylindrical tube has to be applied to explain the experimental results in the frequency range measured. The values of saturation magnetization, g-factor and anisotropy field have been estimated from the frequency dependence of the field for resonance. (C) 2002 Elsevier Science B.V. All rights reserved.