EFFECT OF SM SUBSTITUTION ON STRUCTURE AND MAGNETIC-PROPERTIES OF HIGH-CARBON ER2FE17CY COMPOUNDS

The carbides (Er1-xSmx)2Fe17Cy, (0 less-than-or-equal-to x less-than-o r-equal-to 0.8) with a carbon concentration up to y=3.0 for the Er-ric h region and up to y = 1. 5 for the Sm-rich region have been successfu lly prepared by melt spinning. They are found to crystallize in the he xagonal Tb2Ni17-type or the rhombobedral Tb2Zn17-type structure and to be stable at high temperature. The introduction of the interstitial c arbon results in a large increase in the unit-cell volumes and Curie t emperatures. The room-temperature saturation magnetization is found to increase with increasing carbon or samarium concentrations. X-ray dif fraction studies of magnetically aligned powder show that the samples with x < 0. 2 or y less-than-or-equal-to 0. 5 exhibit easy plane aniso tropy while the samples with x greater-than-or-equal-to 0. 2 and y gre ater-than-or-equal-to 1. 0 exhibit easy c-axis anisotropy at room temp erature. For (Er0.2Sm0.8)2Fe17C1.5, the, room-temperature anisotropy f ield is found to be 8 T, which is comparable to that of Nd2Fe14B.