Here are three categories:
First Category, Rare Earth permanent magnetic materials: The permanent magnetic materials for Rare Earth Element and iron group elements as the main components of intermetallic, also known as intermetallic compounds. Common examples are Maglev train, wind turbines, and motor types.
SSecond, metallic permanent magnetic materials: This is a large class of alloy permanent magnetic materials with iron and iron group elements such as nickel and cobalt, which have been developed and applied earlier, there are two kinds of permanent magnetic alloys, AlNiCo series and FECRCO series. Common such as a variety of sound, guitar, sensors, tachometer and other types of instrumentation.
The third category, ferrite permanent magnetic materials: This is the main components of iron oxide composite oxide strong magnetic materials and magnetic ordered materials such as antiferromagnetic materials in the narrow sense. It is characterized by high resistivity and is particularly useful in high frequency and microwave applications.