Fun with magnets – Demagnetising a Permanent Magnet


What is Magnetisation?

Magnetisation is a process in which any non-magnetic material is magnetised. This process is carried out to convert a non-magnetic material into a temporary magnet or a permanent magnet.

What is Demagnetisation?

Demagnetisation is a process in which a temporary or a permanent magnet is demagnetised.

That is, it is a process in which ‘magnetism’ is taken away from the magnet.

How to demagnetise a magnet?

●     Demagnetising a temporary magnet

When an iron nail is brought near one of the poles of a magnet, it gets attracted to it. This nail is now magnetised. It is because it is placed under the magnetic field of the magnet and hence it acquires magnetism from this magnet. If any other lightweight ferromagnetic material is brought near it, then this nail will attract that material.

As soon as this nail is taken away from the magnet, it loses its magnetism quickly. It will no longer attract any material. Now, this iron nail cannot act as a temporary magnet anymore! When the nail is removed from the external magnetic field of the magnet, it is actually demagnetised.

Demagnetising a temporary magnet

●     Demagnetising a permanent magnet

Permanent magnets lose their magnetism eventually. But it takes a very long time for them to completely demagnetise on their own. But this process can be quickened.

  • Hammering a permanent magnet can demagnetise it. Because the alignment of atoms of the material is broken, it ultimately loses its
  • Heating a permanent magnet for a long time will cause it to slowly start losing its magnetism, and be