Diamagnetism

Diamagnetism. Property of materials by which they are weakly magnetized in the opposite direction to an applied magnetic field. Diamagnetic materials are weakly repelled by magnets. The induced magnetism disappears if the applied field does. All materials have diamagnetism, but the term diamagnetic is only used for those in which this property is not masked by another type of magnetic effect.

Summary

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• 1 Explanation
• 2 Diamagnetic Materials
• 3 See also
• 4 Bibliography
• 5 Sources
• 6 External links

Explanation

In electromagnetism , diamagnetism is a property of materials that consists of being repelled by magnets. It is the opposite of ferromagnetic materials which are attracted to magnets. The phenomenon of diamagnetism was first discovered and nominated in September 1845 by Michael Faraday when he saw a piece of bismuth that was repelled by any pole of an Imam ; indicating that the external field of the magnet induces a magnetic dipole in the opposite direction bismuth.

Diamagnetic Materials

The vast majority of substances are diamagnetic, since all pairs of electrons with opposite spin contribute weakly to diamagnetism, and only in cases where there are mismatched electrons is there a paramagnetic (or more complex) contribution in the opposite direction. Some examples of diamagnetic materials are: metallic bismuth, hydrogen , helium and other noble gases, sodium chloride , copper, gold , silicon , germanium, graphite, bronze and sulfur . Note that not all of these have an even number of electrons.

Pyrolytic graphite, which has an especially high diamagnetism, has been used as a visual demonstration, since a thin layer of this material levitates (by repulsion) on a sufficiently strong magnetic field (at room temperature). Experimentally, it is verified that the diamagnetic materials have a magnetic permeability less than unity, and a negative magnetic susceptibility, practically independent of temperature, and generally of the order (in cegesimal units) of emu / mol, where M is the molecular mass. For many coordination compounds, a more accurate estimate is obtained using Pascal’s tables. In diamagnetic materials, the magnetic flux decreases and in paramagnetic ones the magnetic flux increases.

diamagnetism