A neodymium magnet is the most widely used type of rare-earth magnet.
It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the tetragonal crystalline structure.
Demagnetization is a process that means removing magnetic properties from it.
It can be done by heating past the curie temperature, applying a strong magnetic field, applying alternating current, or hammering the metal.
Therefore, by heating neodymium magnets over the curie temperature, which is above , and also a suitable ac field can also be used to demagnetize it at a lower temperature.