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paramagnetism




A type of magnetism that occurs in substances with a positive magnetic susceptibility. It results in these substances being weakly attracted by a strong magnet. Paramagnetism is caused by the presence of at least one unpaired electron orbital (i.e., an unpaired spin) in the atoms, molecules, or ions of the paramagnetic material, which results in these particles having a dipole moment. An applied magnetic field tends to align these dipoles in such a way that for small field and high temperatures the induced field is proportional to the applied field; the magnetization is in the same direction as the applied field.

Paramagnetism is normally stronger than diamagnetism, and the effect varies inversely with temperature. Below the Curie temperature, certain paramagnetic materials exhibit ferromagnetism.

Examples of paramagnetic materials at room temperature include aluminum (Al), manganese (Mn), platinum (Pt), oxygen (gas and liquid), and rare earth ions.


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   • ELECTRICITY AND MAGNETISM