Atomic Theory of Magnetism

The atomic theory of magnetism was given by Weber and modified by Ewing. According to this theory:

Magnetic Materials

Magnetic materials are those materials that can be either attracted or repelled when placed in an external magnetic field and can be magnetized themselves.

Examples: iron or its alloys which are used in various electrical appliances like generators, televisions, cassette recorders, magnetic core computer memories etc. to increase the magnetic flux without increasing the current.

The magnetic properties of a material depend whether it has permanent dipole moment or not, if yes then question arises, how these dipoles are oriented with respect to each other ? On the basis of orientation, the magnetic materials are classified into five categories (a) Diamagnetic   (b) Paramagnetic   (c) Ferromagnetic   (d) Anti – ferromagnetic and   (e) Ferrimagnetic.

Note: This article is referred from my book “Electrical Engineering Materials” having ISBN 978-81-272-5069-0