Session UA01 - Cent. Symposium: The History of Magnetism.
INVITED session, Thursday morning, March 25
Ballroom I, GWCC
Two useful books for reviewing the field of magnetic materials over the past 100 years are "Magnetic Induction in Iron and Other Metals," by J. A. Ewing (3rd edition, 1901), and "Ferromagnetism," by R. A. Bozorth, 1951. Appearing very nearly 100 and 50 years ago, these works summarized the field of magnetic materials in a way that no single author has since been able to achieve. In 1900, iron was the principal soft magnetic material, and hardened steel was used for permanent magnets. Most of the soft magnetic materials in use today were available in 1950; the only significant additions are the amorphous and nanocrystalline materials. However, the development of magnetically hard ferrites came mostly after 1950, as did all the development of rare-earth permanent magnets. More recent work in thin films, magnetic bubbles, magneto-optics, and magneto- resistance has all been driven by the needs of the computer industry, and often produces materials that lie between the conventional definitions of hard and soft. note