| Themes > Science > Physics > Solid State Physics > Magnetic Properties of Solids > Diamagnetism and Paramagnetism > Paramagnetism |
Paramagnetism is a kind of magnetism characteristic of materials weakly attracted by a strong magnet, named and extensively investigated by the British scientist Michael Faraday beginning in 1845. Most elements and some compounds are paramagnetic. Strong paramagnetism (not to be confused with the ferromagnetism of the elements iron, cobalt, nickel, and other alloys) is exhibited by compounds containing iron, palladium, platinum, and the rare-earth elements. In such compounds atoms of these elements have some inner electron shells that are incomplete, causing their unpaired electrons to spin like tops and orbit like satellites, thus making the atoms a permanent magnet tending to align with and hence strengthen an applied magnetic field. Strong paramagnetism decreases with rising
temperature because of the re-alignment produced by the greater random
motion of the atomic magnets. Weak paramagnetism, independent of
temperature, is found in many metallic elements in the solid state, such
as sodium and the other alkali metals, because an applied magnetic field
affects the spin of some of the loosely bound conduction electrons. The
value of susceptibility (a measure of the relative amount of induced
magnetism) |
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