Magnetic materials for recording: An overview with special emphasis on particles (invited)

Abstract

Modern recording media—tapes and disks—are made using a broad variety of magnetic materials, each presenting a unique combination of strengths and weaknesses. Although recording surfaces can be made by the deposition of thin magnetic films on a support material, most commercially available media are made by coating the support material with a dispersion of magnetic particles in an organic binder. This approach has been used for decades and is capable of being extended to future applications. The particles that are dispersed in such coatings can be of many compositions. The general requirements placed on magnetic recording materials are outlined, and the relative merits of the most significant candidates are described. Of the important particulate materials, the cobalt-modified iron oxides are treated most fully, because of their economic as well as technical interest.