High frequency measurement technique for patterned soft magnetic film permeability with magnetic film/conductor/magnetic film inductance line

This article describes a new technique in the 1 MHz to 1 GHz range for measuring the permeability of patterned soft magnetic films. An inductance line with a magnetic film/conductor/magnetic film structure makes it possible to measure permeability at frequencies of up to 1 GHz because of the low stray capacitance and high resonance frequency of the electric circuit. The magnetic film pattern is designed so that the demagnetizing field can be ignored, and the absolute permeability value is estimated by analyzing the magnetic circuit. No anomaly, which may be caused by a magnetic charge at the pattern edge or a dimensional resonance, is observed using this pattern. Also, the relative permeability

μ

′ r

(0)

and ferromagnetic resonance frequency f_k measured with this technique, are confirmed to be in good agreement with the values calculated from static magnetic properties.