Thursday, February 09, 2006
diamagnetism - definition - electromagnetism and statistical physics
Definition: Phenomenon in some materials in which the susceptibility is negative, i.e. the magnetisation opposed the magnetising force. It arises from the precession of spinning charges in a magnetic field. The magnetisation is in the opposite direction to that of the applied field, i.e. the susceptibility is negative. Although all substances are diamagnetic, it is a weak form of magnetism and may be masked by other, stronger forms. It results from changes induced in the orbits of electrons in the atoms of a substance by the applied field, the direction of change (in accordance with Lenz's law) opposing the applied flux. There is thus a weak negative susceptibility and a relative permeability of slightly less than one.