Chapter 1 Magnetism and magnetic materials: Historical developments and present role in industry and technology

Abstract

Publisher Summary This chapter outlines the history of magnetism and magnetic materials. It discusses the role of magnetism and magnetic materials in modern technology, especially in the context of power generation and distribution, telecommunication, and data storage. Some statistical figures on the economic significance of magnetic materials are described in the chapter. The largest quantities of magnetic material enter the field of electric power generation and distribution, a field that is historically the major application of magnetism. For this function, the aim is to reach the highest possible saturation magnetization and the lowest possible total loss, properties that are best met in iron-based alloys such as silicon–iron sheet and grain-oriented sheet. A second area of great and rapidly increasing importance is that of magnetic materials for information storage and processing. The amount of material involved in these fields is much smaller, but their economical significance is larger than that of electrical steels. Amongst information-storing materials, magnetic tapes and discs are the most important groups. Tape and disc techniques are both based on the same physical principle, the association of a bit of information with the direction of the magnetization in a small area of the material. Communication is the third important field of application of magnetic materials. This field includes telephony, radio and television broadcasting and receivers, and radar, all of which techniques use medium to very high frequencies.