Question

Explain:
i) Paramagnetism

ii)Diamagnetism

iii) Ferromagnetism

Answer 1

$Paramagnetism$ refers to a property of materials that are weakly attracted to a magnetic field. When exposed to an external magnetic field, internal induced magnetic fields form in the material that are ordered in the same direction as the applied field. Once the applied field is removed, the material loses its magnetism as thermal motion randomizes the electron spin orientations. Paramagnetism results from the presence of least one unpaired electron spin in the material's atoms or molecules. So, any material that possesses atoms with incompletely filled atomic orbitals is paramagnetic.

$Diamagnetism$ is a very weak form of magnetism that is induced by a change in the orbital motion of electrons due to an applied magnetic field. This magnetism is nonpermanent and persists only in the presence of an external field. The magnitude of the induced magnetic moment is very small, and its direction is opposite to that of the applied field.

$Ferromagnetism$ comes from the term ‘ferrous’ meaning iron, the first type of metal discovered to exhibit attraction to magnetic fields. Ferromagnetism is the basic method in which a compound forms a permanent magnet or is attracted to a magnetic field. In a nonmagnetic compound, permanent magnetic dipoles tend to line up antiparallel in order to cancel each other out. In ferromagnetism, however, the opposite is true. Ferromagnetism arises from the spontaneous lining up of permanent dipoles parallel to each other within a compound. These magnetic dipoles arise from the movement of pairs of electrons within their atomic/molecular orbital's. Ferromagnetism is normally seen in materials that have partially filled outer valence shells.