What is "antiferromagnetism"

n. (context physics English) a phenomenon, similar to ferromagnetism, in which magnetic domains line up in a regular pattern, but with neighbouring electron spins pointing in opposite directions; materials showing this effect are either ferrimagnetic or diamagnetic, and become paramagnetic above the Neel temperature

n. magnetic field creates parallel but opposing spins; varies with temperature

In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions. This is, like ferromagnetism and ferrimagnetism, a manifestation of ordered magnetism. Generally, antiferromagnetic order may exist at sufficiently low temperatures, vanishing at and above a certain temperature, the Néel temperature (named after Louis Néel, who had first identified this type of magnetic ordering). Above the Néel temperature, the material is typically paramagnetic.