Coaxial measurements of microwave permeability of thin supermalloy films under magnetic bias

Abstract

Abstract We present investigation of microwave permeability of thin supermalloy films deposited on a flexible substrate. The permeability measurements are performed by transmission-reflection technique in a coaxial line under external magnetic bias in the frequency range of 100\u202fMHz–20\u202fGHz. It is shown that demagnetization does not affect the measurements when bias is above 150\u202fOe. Magnetic characteristics of the films are determined by two approaches: (i) fitting of the resonant frequency dependence on magnetic bias by Kittel s equation and (ii) calculation of the parameters from the Landau–Lifshitz–Gilbert dispersion law. Both approaches give close results for values of magnetoelastic field, anisotropy field, saturation magnetization, and damping factor.