Permeability measurement in the GHz range for soft-magnetic film using the M/C/M inductance-line

Abstract

This work reports a new technique for measuring permeability of magnetic alloy films above 1 GHz by using an inductance-line, which has a magnetic alloy films(M)/conductor(C)/magnetic alloy films(M) stacked structure and is installed in a microstrip circuit. The imaginary part of the relative permeability /spl mu//sub r/" was estimated from the magnetic absorption in the M/C/M inductance-line, by analyzing its transmission characteristics. The Kramers-Kronig relation was used for the transformation from /spl mu//sub r/" to the real part /spl mu//sub r/'. Complex relative permeability was measured in the 1 MHz-20 GHz frequency range for NiFe-SiO/sub 2/, CoZrNb-SiO/sub 2/ and CoFe-SiO/sub 2/ multilayer films. The /spl mu//sub r/-f characteristics, static relative permeability /spl mu//sub r/"(0) and ferromagnetic resonance frequency f/sub k/ values were confirmed to agree with those obtained by the conventional M/C/M technique and by calculation.