The antiferromagnetism (griech.: anti approximately; lat.: ferrum iron; of griech.: magnetis (lithos) stone from Magnesien) is a cooperative, magnetic phenomenon, which and. A. by Louis Néel one examined in detail.
With this effectthe spins of the atoms with a constant angle of rotation different of zero are to each other aligned and compensate themselves accurately over the entire crystal. In the simplest case this angle of rotation is 180°, so that the spins of neighbouring atoms stand antiparallelly to each other.
With the more well-known ferromagnetism the spins are parallelto each other aligned, whereby a permamentes macroscopic magnetic field is developed. Below the Néel temperature in such a way specified the permeability is nearly temperature independent with the antiferromagnetism. Above this temperature is the behavior of the body paramagnetic.