PERMEABILITY MEASUREMENT IN THE GHZ RANGE FOR SOFT-MAGNETIC FILM USING THE M/C/M INDUCTANCE-LINE

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 mu(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 mu(r)'' to the real part mu(r)'. Complex relative permeability was measured in the 1 MHz-20 GHz frequency range for NiFe/SiO2, CoZrNb/SiO2 and CoFe/SiO2 multilayer films. The mu(r) - f characteristics, static relative permeability mu(r)' (0) and ferromagnetic resonance frequency f(k) values were confirmed to agree with those obtained by the conventional M/C/M technique and by calculation.