Magnets are commonly used in all sorts of applications such as speakers and motors, they can even be found in classrooms to help teach science. However, there may be a time when you need to demagnetise a magnet, but how do you go about this?
Demagnetising a magnet involves reducing, removing, or eliminating its magnetic field, this is typically most useful when a magnet begins to interfere with electronic devices, or you need to dispose of a magnet.
There are five different ways to demagnetise a magnet and, in this blog, we will explore the multiple ways to demagnetise a magnet.
Heating The Magnet
One of the easiest methods to demagnetise a magnet is to apply heat and heat the magnet to a high temperature, different magnet materials will have different resistance to high temperatures.
The heat will cause the magnetic domains in the magnet to lose their alignment and reduce its magnetic field, however, this method can cause permanent damage to the magnets if it is exposed to high temperatures for too long.
Striking The Magnet
Another method used to demagnetise a magnet is to strike it, when the magnet is struck, the magnetic domain inside becomes disordered, reducing the magnetic field.
It’s important to strike the magnet with a strong force to ensure it is correctly demagnetised completely, however, this method can also cause damage to the magnet.
Alternating Current
Alternating current (AC) can be used to demagnetise a magnet and involves passing through AC through a coil placed near the magnet. The AC current generates a magnetic field that cancels out the magnetic field of the magnet, which demagnetises it.
This method is commonly used in demagnetising large objects such as motors and generators.
Electromagnets
Electromagnets are a coil of wire that generates a magnetic field when an electric current flows through them, by passing a strong AC current through the electromagnets, a magnetic field can be generated that is strong enough to demagnetise the magnet.
Reverse The Magnetic Field
A magnets magnetic field can also be demagnetised by reversing its polarity, this can be done by placing the magnet in a magnetic field that is opposite to its own.
The opposite field cancels out the magnetic field of the magnet, which reduces its strength.