Editing Diamagnetism (section)

=== Levitation ===<!-- This section is linked from [[Magnetic levitation]] -->
{{main|Magnetic levitation#Diamagnetic levitation}}
[[File:Frog diamagnetic levitation.jpg|thumb|A live [[frog]] levitates inside a {{convert|32|mm|2|abbr=on}} diameter vertical bore of a [[Bitter solenoid]] in a magnetic field of about 16 [[tesla (unit)|teslas]] at the [[Radboud University Nijmegen|Nijmegen High Field Magnet Laboratory]].<ref>{{cite web |year=2011 |title=Diamagnetic Levitation |website=High Field Laboratory |publisher=[[Radboud University Nijmegen]] |url=https://www.ru.nl/hfml/research/levitation/diamagnetic-levitation/ |access-date=26 September 2020 |archive-date=28 March 2019 |archive-url=https://web.archive.org/web/20190328033931/https://www.ru.nl/hfml/research/levitation/diamagnetic-levitation/ |url-status=dead }}</ref> ]]

Diamagnets may be levitated in stable equilibrium in a magnetic field, with no power consumption. [[Earnshaw's theorem]] seems to preclude the possibility of static magnetic levitation. However, Earnshaw's theorem applies only to objects with positive susceptibilities, such as ferromagnets (which have a permanent positive moment) and paramagnets (which induce a positive moment). These are attracted to field maxima, which do not exist in free space. Diamagnets (which induce a negative moment) are attracted to field minima, and there can be a field minimum in free space.

A thin slice of [[pyrolytic graphite]], which is an unusually strongly diamagnetic material, can be stably floated in a magnetic field, such as that from [[Rare-earth magnet|rare earth]] permanent magnets. This can be done with all components at room temperature, making a visually effective and relatively convenient demonstration of diamagnetism.

The [[Radboud University Nijmegen]], the [[Netherlands]], has conducted experiments where water and other substances were successfully levitated. Most spectacularly, a live frog (see figure) was levitated.<ref>{{cite web |year=2011 |title=The Real Levitation |website=High Field Laboratory |publisher=[[Radboud University Nijmegen]] |url=http://www.ru.nl/hfml/research/levitation/diamagnetic/ |access-date=26 September 2011 |archive-date=27 August 2013 |archive-url=https://web.archive.org/web/20130827232750/http://www.ru.nl/hfml/research/levitation/diamagnetic/ |url-status=dead }}</ref>

In September 2009, NASA's [[Jet Propulsion Laboratory]] (JPL) in Pasadena, California announced it had successfully levitated mice using a [[superconducting magnet]],<ref>{{cite journal |last1=Liu |first1=Yuanming |last2=Zhu |first2=Da-Ming |last3=Strayer |first3=Donald M. |last4=Israelsson |first4=Ulf E. |year=2010 |title=Magnetic levitation of large water droplets and mice |journal=[[Advances in Space Research]] |doi=10.1016/j.asr.2009.08.033 |bibcode=2010AdSpR..45..208L |volume=45 |issue=1 |pages=208–213}}</ref> an important step forward since mice are closer biologically to humans than frogs.<ref>{{cite web |last=Choi |first=Charles Q. |date=2009-09-09 |title=Mice levitated in lab |website=Live Science |url=http://www.livescience.com/animals/090909-mouse-levitation.html |access-date=26 September 2011 |archive-date=4 July 2012 |archive-url=https://web.archive.org/web/20120704082535/http://www.livescience.com/5688-mice-levitated-lab.html |url-status=live }}</ref> JPL said it hopes to perform experiments regarding the effects of microgravity on bone and muscle mass.

Recent experiments studying the growth of protein crystals have led to a technique using powerful magnets to allow growth in ways that counteract Earth's gravity.<ref>{{cite web |last=Kleiner |first=Kurt |date=10 August 2007 |title=Magnetic gravity trick grows perfect crystals |website=[[New Scientist]] |url=https://www.newscientist.com/article/dn12467-magnetic-gravity-trick-grows-perfect-crystals.html |access-date=26 September 2011 |archive-date=4 June 2011 |archive-url=https://web.archive.org/web/20110604043355/http://www.newscientist.com/article/dn12467-magnetic-gravity-trick-grows-perfect-crystals.html |url-status=live }}</ref>

A simple homemade device for demonstration can be constructed out of bismuth plates and a few permanent magnets that levitate a permanent magnet.<ref>{{cite web |date=2 December 2008 |title=Fun with diamagnetic levitation |publisher=ForceField |url=http://www.fieldlines.com/other/diamag1.html |access-date=26 September 2011 |url-status=dead |archive-url=https://web.archive.org/web/20080212011654/http://www.fieldlines.com/other/diamag1.html |archive-date=12 February 2008 }}</ref>