Neél

Néel, written with an acute accent on the e, is a French surname. The most prominent bearer is Louis Eugène Félix Néel (1904–2000), a French physicist who made foundational contributions to the theory of magnetism.

Néel introduced the concepts of antiferromagnetism and ferrimagnetism and developed quantitative models of exchange interactions in solid-state systems. He showed how spins on different sublattices can align antiparallel, producing little or no net magnetization in the absence of a magnetic field. His work laid the groundwork for the modern understanding of magnetic ordering in crystals and insulators.

For his contributions to magnetism, Néel was awarded the Nobel Prize in Physics in 1970. The prize recognized his elucidation of the mechanisms of magnetic ordering and his development of theoretical descriptions of antiferromagnetism and ferrimagnetism.

Several terms in magnetism are named after Néel. The Néel temperature (TN) is the temperature above which an antiferromagnetic material becomes paramagnetic and below which long-range antiferromagnetic order appears. The Néel state or Néel ordering refers to the antiparallel arrangement of spins on neighboring sublattices in an antiferromagnet. The order parameter describing this arrangement is commonly referred to as the Néel vector in some theoretical treatments.

Beyond Louis Néel, the surname appears in various contexts within French-speaking cultures and in scientific literature related to magnetism.