Magnetic Alloys of Iron Nickel, and Cobalt

Recent investigations of magnetic properties of alloys of iron, nickel and cobalt have resulted in the discovery of materials of remarkable magnetic properties previously unknown. In a brief review, early experiments that led to the discovery of these materials and the magnetic properties of the entire field are discussed. Those groups of alloys of outstanding scientific and technical importance such as the permalloys and the perminvars and special heat treatment required for development of special magnetic properties are taken up in detail. A theory is suggested to account for some of the magnetic characteristics, and a few of the practical applications of these materials are described.