Magnetic Moment and Magnetization

Magnetismhas engaged explorers and scientists for over two millennia. The ancient Greeks and Turks noted the attraction between magnetite (lodestone) and iron (Cullity and Graham, 1978). Explorers used lodestone’s magnetization to construct compass needles used to point to the direction of the earth’s magnetic North Pole. This singularly important device aided in navigation and the exploration of the planet. Today, the miniaturization of magnetic sensors has propelled the magnetic recording industry as well as contributed to far-reaching applications such as planetary exploration (Diaz-Michelena, 2009). Michael Faraday’s (1791–1867) discovery of electromagnetic inductionprovides theprinciple forunderstanding theoperationofelectric generators, transformers,and a variety of other magnetic devices. The quantum mechanical description of the origin of atomic magnetic dipole moments provides the basis for understanding a variety of disparate phenomena including the magnetic response of materials. The intrinsicmagnetic properties ofmaterials refer to: