Magnetic oxides: ferrites
Permanent magnets

These materials were developed in the early 1950s and industrialized following publications and patents by Philips. They are iron oxide ceramics with the general properties of all ceramic bodies, as opposed to metallic bodies such as alnicos.

Since the 1970s, production of ferrite-type magnets has outstripped that of other types. Today, ferrite-type magnets are by far the most widely used in the world. This is mainly due to the following reasons:

• the material is cheap;

• the raw materials used are neither rare nor strategic;

• the magnetic properties obtained have led to the development of numerous applications in the consumer markets.

Although these materials have been known for decades, research is still being carried...