Magnetism and Magnetic Materials

Hard and Soft Magnetic Materials

Magnetic materials include hard magnets and soft magnets. Hard magnet is also known as permanent magnet, which means a large magnetic field is needed to align the magnetic domains. Soft magnetic materials are easily magnetized and demagnetized. The main difference between hard magnetic materials and soft magnetic materials is that hard magnetic materials have high anisotropy field, high coercivity, large hysteresis loop area, and large magnetic field required for technical magnetization to saturation. Due to the low coercivity of the soft magnetic material, it is easy to demagnetize after the technical magnetization reaches saturation and the external magnetic field is removed, while the hard magnetic material due to the high coercivity, after the technical magnetization to saturation and the magnetic field is removed, it will remain long-term very strong magnetism, so hard magnetic materials are also called constant magnetic materials.