Ferrite at HF -Susceptibility spectroscopy

Soft ferrites are used as the cores of low power radio frequency inductors and transformers. Ferrites are characterised by their complex susceptibility spectra; the data books show a wide choice. However, the causes underlying these families of curves are not clear; explanations usually invoke resonance effects. An explanation is attempted in terms of relaxation processes alone. A simple addition of relaxations is found to work well for materials with a `relaxation character´. Materials with a `resonance character´ require the subtraction of susceptibilities. However, models of materials with a strong `resonance character´ seem to require the subtraction of unfeasibly large susceptibilities.