INTRINSIC AND EXTRINSIC PROPERTIES OF RARE EARTH-TRANSITION METAL-COMPOUNDS AND PERMANENT-MAGNETS

The revolutionary progress made in the field of permanent magnets over the past 25 years has been almost entirely due to a concentrated research effort in the field of rare earth-transition metal compounds. This paper discusses the unique intrinsic properties of such compounds as precursors for permanent magnets, and outlines possible coercivity mechanisms and their relationship with microstructure in the two main families of R-T permanent magnets: Sm-Co and Nd-Fe-B. The relationship between intrinsic and extrinsic properties is also briefly discussed. © 1990.