Diamagnetism
Diamagnetism
is a form of magnetism where certain minerals are repelled
by an externally applied magnetic field, and form internal
induced magnetic
fields in the direction opposite to that of the applied magnetic field, thus causing a
repulsive effect.
Consequently, diamagnetism is a form of magnetism
that is only exhibited by a substance in the presence of an externally
applied magnetic field. It is generally quite a weak effect in most
materials, although superconductors exhibit a strong effect. Barite,
Bismuth and
Ludlamite are
diamagnetic. Bismuth is the most naturally diamagnetic
element and has one of the lowest values of thermal conductivity among metals.
Paramagnetism
Paramagnetism is a form of magnetism where certain minerals are attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. Xenotime is
paramagnetic.
History
In 1778
S. J. Bergman was the first individual to observe that bismuth was repelled by magnetic fields. However, the term "diamagnetism" was coined by British
scientist Michael Faraday
in September 1845, when he realized that all materials in nature
possessed some form of diamagnetic or paramagnetic response to an applied magnetic
field. Paramagnetism was discovered and originally researched by Michael Faraday.
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