ABSTRACT
Magnetism is an open œeld in which physicists, electrical engineers, material scientists, mathematicians, chemists, metallurgists, and others practice together.
Today information technologies ranging from personal computers to mainframes use magnetic materials to store information on tapes, °oppy diskettes, and hard disks. Our seemingly insatiable appetite for more computer memory will probably be met by a variety of magnetic recording technologies based on nanocrystalline thin-œlm media and magneto-optic materials. Personal computers and many of our consumer and industrial electronics components are now powered largely by lightweight switch-mode power supplies using new magnetic materials technology that was unavailable 20 years ago. Magnetic materials touch many other aspects of our lives. Each automobile contains dozens of motors, actuators, sensors, inductors, and other electromagnetic and magneto-mechanical components using hard (permanent) as well as so§ magnetic materials. Electric power generation, transformation, and distribution systems rely on hundreds of millions of transformers and generators that use the principles of electromagnetic œelds as well. Finally, magnetism is present in telecommunication systems, such as mobile phones, electronic article surveillance, asset protection, and access control because of the presence of oscillating circuits and resonators working at microwave frequencies.
