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