METHOD OF REVERSIBLE PERMEABILITY MEASUREMENT FOR SOFT MAGNETIC COMPOSITES
Zuzana Birčáková – Peter Kollár – Bernd Weidenfeller – Ján Füzer
A setup for measurement of the reversible relative permeability as a function of applied magnetic field was adapted for ring-shaped soft magnetic composite samples, based on the lock-in amplifier reading of the induced voltage. Functioning of the measurement setup is described and illustrated on two types of soft magnetic composite materials: Fe-phenolphormaldehyde resin samples differing in resin content and mean particle size and FeSi-polypropylene samples with different polypropylene content. The results present the possibilities and limitations of the measurement method, together with the procedure of finding the most appropriate frequency and amplitude of AC magnetic field depending on particular material. From the measured re-versible permeability the proportions of reversible magnetization processes within the total magnetization process were deter-mined, as the ratio of reversible to differential permeability.
Keywords: magnetic measurement, reversible relative permeability, magnetization processes, composite material