Non-linear tunneling charge transport in soft ferrites

To better understand the high-frequency magnetic loss mechanisms in soft ferrites, we measured the conductivity of the soft ferrites for large values of the electric field. We found that the conductivity is highly non-linear. We show that this non-linearity is consistent with charge tunneling through thin insulating films separating adjacent ferrite grains. This non-linear conductivity can be used to obtain observed flux density dependence of the high-frequency magnetic loss. This flux dependence of the high-frequency loss previously remained anomalous.