1. Physical properties of ferrites

1.1 Crystallographic structure and chemical composition

Ferrites are ionic compounds whose main constituents are trivalent iron and oxygen. Soft ferrites used for their high permeability and/or low losses have a spinel-type cubic crystallographic structure, similar to that of MgAl ₂ O ₄ spinel.

The chemical formulae of spinel-structured ferrites are written MeFe ₂ O ₄ . In the simplest structure, Me represents a divalent metal cation, with iron in a trivalent state. The most interesting ferrites for applications are complex, in which case Me represents a combination of divalent...