In the natural state, magnetism is basically undiminished.
The main factors of magnetic attenuation are.
1. High temperature or low temperature.
2. Reverse the external magnetic field, the alternating magnetic field
3. Deformation (for certain magnets such as ferrochrome)
4. Vibration impact and ferromagnetic adsorption (for low coercive force magnets such as aluminium nickel and cobalt)
5. Oxidation corrosion
High and low temperature
First, the magnetic induction intensity decreases with the increase of temperature.
The second is that coercive force decreases with temperature.
The reasons are more complex, and unlike upstairs, he is closer to the paramagnetic substance.
In addition to the alignment of the spin magnetic moment, the permanent-magnet material is more dependent on structure and orbital magnetism.
Rectangular magnetocrystalline anisotropy is a source of coercive force.
Of course, the high temperature and the low temperature to a certain degree, the magnetic crystal anisotropy is zero, or.
The change of direction, the permanent magnet is invalid.
High and low temperatures may also cause the crystal structure to change naturally and lose magnetism.