3. Ceramic or hard ferrite materials

3.1 General

There are two types of magnetic ferrites: soft and hard:

• the former, with their low coercive field strength, are used mainly in electronic applications, particularly at high frequencies (cf. in the Electronics treatise, article ) ;

• the latter are used to manufacture ceramic magnets. Initially, these materials were studied in the 1950s by the Philips laboratories in Eindhoven [27] , whose work was based on the Stoner-Wohlfarth theory of monodomain fine grains [1] , according to which coercivity is proportional to anisotropy (see article...