Editing Magnet (section)

== Demagnetizing ferromagnets ==
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Magnetized ferromagnetic materials can be demagnetized (or degaussed) in the following ways:
* [[Heat]]ing a magnet past its [[Curie temperature]]; the molecular motion destroys the alignment of the magnetic domains, completely demagnetizing it
* Placing the magnet in an alternating magnetic field with intensity above the material's [[coercivity]] and then either slowly drawing the magnet out or slowly decreasing the magnetic field to zero. This is the principle used in commercial demagnetizers to demagnetize tools, erase credit cards, [[hard disk]]s, and [[degausser|degaussing coils]] used to demagnetize [[Cathode-ray tube|CRTs]].
* Some demagnetization or reverse magnetization will occur if any part of the magnet is subjected to a reverse field above the magnetic material's [[coercivity]].
* Demagnetization progressively occurs if the magnet is subjected to cyclic fields sufficient to move the magnet away from the linear part on the second quadrant of the B–H curve of the magnetic material (the demagnetization curve).
* Hammering or jarring: mechanical disturbance tends to randomize the magnetic domains and reduce magnetization of an object, but may cause unacceptable damage.