Permeability of Soft Magnetic FeCoV-Composites for Varying Filler Fractions

The dependence of permeability on the magnetic field in the initial magnetization curve for different Fe(49)Co(49)V(2)-polymer composites is investigated. For a measurement frequency of f = 1 Hz and a low filler fraction of x = 0.1 the permeability is nearly constant with increasing magnetic field with a small maximum at H = 26100 A/m. Increasing filler fraction causes an increase of initial permeability and also the maximum permeability becomes more and more distinctive. Additionally the position of the maximum shifts to a lower magnetic field of H = 3027 A/m for filler fraction x = 0.8. At this filler fraction the maximum permeability is mu(max) = 57 and the initial permeability is mu(i) = 36. At the magnetic field where the maximum permeability was found also the frequency dependence from 1 Hz to 2000 Hz of the permeability was estimated. While the permeability is nearly constant in the whole examined frequency range for a filler fraction x <= 0.2, a higher filler fraction causes a reduction of permeability at higher frequencies. For the composite with 80-vol.% Fe(49)Co(49)V(2) content the permeability is decreased for frequencies f > 100 Hz.