Rare Earth Magnet Basics / Glossary of Magnet Terms / Coercive force or coercivity
- Coercive force or coercivity
- This means the value of the external magnetic field that brings to zero the magnetization or magnetic flux density of a magnetic body when that external magnetic field is caused to operate in the opposite direction from the orientation of the magnetization of the magnetic body. The value of the external magnetic field when the magnetic polarization (or magnetization) and magnetic flux density of the magnetic body come to zero are written as HcJ and HcB to distinguish them, but when evaluating magnetic characteristics, normally the coercive force means HcJ. This means the stability of magnetization in the face of an external magnetic field or the capacity to resist an external magnetic field. Material with high coercive force is hard magnetic material and material with low coercive force is soft magnetic material. This is the most important characteristic for a permanent magnet material.
