Generally, iron is not a magnet. However, near the magnet, it is affected by the magnet and gets the magnet's property. Therefore, iron sticks to the magnet.
In this way, the material that becomes magnetic by the magnet is called the ferromagnetic material.
When a strong shock or heat is applied, the magnetization is erased.
- Paramagnetic substance : An external magnetic field weakly magnetizes it. When the magnetic field is removed, it returns to its original state. (Aluminum, tin, platinum, iridium, oxygen, air...)
- Ferromagnetic substance : An external magnetic field strongly magnetizes it. The magnetic field is maintained even if the magnetic field is removed. (Iron, nickel, cobalt...)
- Diamagnetic substance : A material magnetized in the opposite direction by an external magnetic field. (Hydrogen, water, crystal, lead, copper, zinc, biscuit, carbon...)