TEMPERATURE DEPENDENCE OF MAGNETIC ANISOTROPY OF Er2Co17, Tm2Co17 AND Sm2Co17.

The temperature dependence of the anisotropy field and the anisotropy constants were measured from 4. 2K to 300K for Er//2Co//1//7, Tm//2Co//1//7 and Sm//2Co//1//7. Er//2Co//1//7 has a maximum in the anisotropy field at 100K, whereas Tm//2Co//1//7 does not show a maximum. There are two rare earth sites, namely 2(b) and 2(d) in Er//2Co//1//7 and Tm//2Co//1//7. The magnetic moments in the 2(b) sites lie in the plane, whereas in the 2(d) sites they lie along the c-axis. The direction of magnetic moments in Tm//2Co//1//7 or Er//2Co//1//7 is determined by a competition between these two sublattices, which is temperature dependent. The maximum in the anisotropy field comes about in this way. The stabilization energy was computed from point charge calculations and are compared with experimental results. Results on some substituted ternaries of Er//2Co//1//7 and Tm//2Co//1//7 are shown.