NEEL, LOUIS-EUGENE-FELIX

born Nov. 22, 1904, Lyon, France French physicist, corecipient, with the Swedish astrophysicist Hannes Alfvn, of the Nobel Prize for Physics in 1970 for his pioneering studies of the magnetic properties of solids. His contributions to solid-state physics have found numerous useful applications, particularly in the development of improved computer memory units. Nel was professor at the universities of Strasbourg (1937) and Grenoble (194676). During the early 1930s he studied, on the molecular level, forms of magnetism that differ from ferromagnetism. In ferromagnetism, the most common variety of magnetism, the electrons line up (or spin) in the same direction at low temperatures. Nel discovered that in some substances alternating groups of atoms align their electrons in opposite directions (much like placing together two identical magnets with opposite poles aligned), thus neutralizing the net magnetic effect. This magnetic property is called antiferromagnetism. Nel's studies of fine-grain ferromagnetics provided an explanation for the unusual magnetic memory of certain mineral deposits that has provided information on changes in the direction and strength of the Earth's magnetic field. Nel was director of the Polytechnic Institute, Grenoble, from 1971 to 1976 and also of the Centre for Nuclear Studies, Grenoble, from 1956 to 1971. He wrote over 200 works on various aspects of magnetism. Mainly because of his contributions, ferromagnetic materials can be manufactured to almost any specifications for technical applications, and a flood of new synthetic ferrite materials has revolutionized microwave electronics.