Louis Eugène Félix Néel
1904–2000, Lyon, France, Brive-la-Gaillarde, France
French physicist who discovered antiferromagnetism and ferrimagnetism and laid the theory underlying magnetic memory materials.
A pupil of Pierre Weiss in Strasbourg, Néel extended the molecular-field picture to cases where neighboring atomic moments align antiparallel, predicting antiferromagnetism in 1932. Settling in Grenoble, he built the Laboratoire d'électrostatique et de physique du métal into a world center of magnetism, and his studies of small grains also explained the paleomagnetic record of rocks.
Nobel-winning work
Néel's 1970 Nobel Prize honored 'fundamental work and discoveries concerning antiferromagnetism and ferrimagnetism which have led to important applications in solid state physics'. In 1932 he proposed that below a characteristic Néel temperature, exchange interactions can align neighboring spins antiparallel — order invisible to magnetometers but revealed by susceptibility and neutron diffraction.
His 1948 theory of ferrimagnetism, where antiparallel sublattices of unequal moment produce net magnetization, explained ferrites such as magnetite. These materials became the basis of transformer cores, microwave devices and magnetic recording.
Workplaces: University of Grenoble, CNRS
France