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How to Demagnetize a Permanent Magnet

As opposed to temporary magnets, which lose their magnetism when not in the presence of a magnetic field, permanent magnets have their own field and are always magnetized. Most of the common magnets that surround us, including refrigerator magnets, are permanent magnets and are made from one of four natural magnetic materials. Some materials are stronger than others and are harder to demagnetize, but all permanent magnets can be demagnetized in several different ways.

Instructions

- 1
  Heat the magnet to red hot. Heating magnets until they glow red will cause the molecules of the magnet to vibrate to the point that they lose their magnetic orientation. Each type of permanent magnet has its own heat point, called the Curie temperature, at which it will become demagnetized. Lower than the Curie temperature is the Tmax, or temperature at which the magnet will begin to lose magnetism. Magnets heated beyond Tmax will recover their magnetism after they cool.
- 2
  Use a stronger magnet. Stroking a permanent magnet against a stronger magnet repeatedly, and in the direction opposite the attraction, will eventually cause the weaker magnet to lose its magnetism. This is also due to the molecules coming out of magnetic alignment.
- 3
  Hit it. Permanent magnets can also be destroyed by brute force. Striking, hammering, dropping or otherwise repeatedly jarring the magnet will also eventually demagnetize it. The repeated hits to the magnet disrupt the magnetized alignment of the molecules and cause them to change their uniform position.

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