Editing Magnet (section)

=== Magnetic materials ===
{{Main|Magnetism}}

The term ''magnet'' is typically reserved for objects that produce their own persistent magnetic field even in the absence of an applied magnetic field. Only certain classes of materials can do this. Most materials, however, produce a magnetic field in response to an applied magnetic field – a phenomenon known as magnetism. There are several types of magnetism, and all materials exhibit at least one of them.

The overall magnetic behavior of a material can vary widely, depending on the structure of the material, particularly on its [[electron configuration]]. Several forms of magnetic behavior have been observed in different materials, including:
* [[Ferromagnetic]] and [[ferrimagnetic]] materials are the ones normally thought of as magnetic; they are attracted to a magnet strongly enough that the attraction can be felt. These materials are the only ones that can retain magnetization and become magnets; a common example is a traditional [[refrigerator magnet]]. Ferrimagnetic materials, which include [[ferrite (magnet)|ferrites]] and the longest used and naturally occurring magnetic materials [[magnetite]] and [[lodestone]], are similar to but weaker than ferromagnetics. The difference between ferro- and ferrimagnetic materials is related to their microscopic structure, as explained in [[Magnetism]].
* [[Paramagnetic]] substances, such as [[platinum]], [[aluminum]], and [[oxygen]], are weakly attracted to either pole of a magnet. This attraction is hundreds of thousands of times weaker than that of ferromagnetic materials, so it can only be detected by using sensitive instruments or using extremely strong magnets. Magnetic [[ferrofluid]]s, although they are made of tiny ferromagnetic particles suspended in liquid, are sometimes considered paramagnetic since they cannot be magnetized.
* [[Diamagnetic]] means repelled by both poles. Compared to paramagnetic and ferromagnetic substances, diamagnetic substances, such as [[carbon]], [[copper]], [[water]], and [[plastic]], are even more weakly repelled by a magnet. The permeability of diamagnetic materials is less than the [[Vacuum permeability|permeability of a vacuum]]. All substances not possessing one of the other types of magnetism are diamagnetic; this includes most substances. Although force on a diamagnetic object from an ordinary magnet is far too weak to be felt, using extremely strong [[superconducting magnet]]s, diamagnetic objects such as pieces of [[lead]] and even mice<ref>[http://www.livescience.com/animals/090909-mouse-levitation.html Mice levitated in NASA lab] {{webarchive|url=https://web.archive.org/web/20110209062936/http://www.livescience.com/animals/090909-mouse-levitation.html |date=2011-02-09 }}. Livescience.com (2009-09-09). Retrieved on 2011-10-08.</ref> can be [[diamagnetic levitation|levitated]], so they float in mid-air. [[Superconductors]] repel magnetic fields from their interior and are strongly diamagnetic.

There are various other types of magnetism, such as [[spin glass]], [[superparamagnetism]], [[superdiamagnetism]], and [[metamagnetism]].