Rare Earth Magnet Basics / Glossary of Magnet Terms / Initial demagnetization
- Initial demagnetization
- One definition of the drop in the amount of magnetic flux when a magnet is raised to high temperature. There is the reversible demagnetization portion, which is the amount the magnetization recovers if the magnet is remagnetized, and the permanent demagnetization portion, which is not recovered. In general, depending on the type of magnet and differences in the Curie temperature and even for the same type of magnet, the amount of demagnetization varies with the magnetic characteristics (primarily the coercive force) and magnet shape and magnetic circuit configuration (permeance coefficient) and the temperature the magnet is heated to. The higher the Curie temperature, the larger the coercive force, the larger the permeance coefficient, and the better the corrosion resistance of the magnet, the smaller the initial demagnetization. High-temperature demagnetization of a magnet is generated by a combination of initial demagnetization and change over time, as well as permanent demagnetization.
