Permeability of Fine Magnetic Particles: Measurements, Calibration, and Pitfalls

High-frequency permeability spectra of FeSiB coatings prepared with spark-eroded magnetic particles were studied. In order to measure the relative permeability of FeSiB coatings with low permeability more accurately, the calibration procedure of the existing permeameter was modified. The modified permeability spectra indicate that FeSiB coatings have the relative permeability below 10 and appreciable losses at frequencies above ~20 MHz. Permeability spectra of CoTaZr amorphous films with the relative permeability above 600 were used for the comparison