High field magnetic measurements on sintered SmCo5 permanent magnets

Hysteresis loops in fields to 100 kOe have been measured at 300, 77, and 4.20K parallel and perpendicular to the alignment axis in a series of sintered SmCo5 magnets with compositions varying from 16.24 to 17.08 at. percent Sm. Analysis of the data taken perpendicular to the alignment axis permits evaluation of the effective anisotropy constant K1, and also the degree of misorientation of the individual particles. Intrinsic coercive fields H/sub ci/ varied from 0.34 to 16.4 kOe at room temperature. In all samples, H/sub ci/ and K1 increased rapidly with decreasing temperature, roughly doubling between room temperature and 770K. The values of H/sub ci/ and (BH)/sub max/ depend strongly on composition, but the anisotropy does not. Variations in permanent magnet properties are therefore not directly related to variations in the bulk anisotropy