STRUCTURAL AND MAGNETIC STUDIES OF ER(2)FE(17-X)M(X)C(Y) (M=GA AND AL) COMPOUNDS

The effect of Ga and Al substitution for Fe on the structural and magn etic properties of the Er(2)Fe(17-x)M(x)C(y) (M=Ga, Al; x=0-4, y=0-2) compounds was investigated. It was found that Ga is superior to Al in stabilizing the single-phase Er(2)Fe(17-x)M(x)C(y) compounds. Thge hex agonal Th2Ni17-type structure persisted in almost all alloys with the exception of Er2Fe13Ga4C and Er2Fe13Ga4C2. These two compounds exhibit ed a rhombohedral Th2Zn17 structure. Both the Curie temperature and ma gnetization can be enhanced with a certain amount of Ga or Al substitu tion. But they decreased almost monotonically with the increase of Ga or Al content in Er(2)Fe(17-x)M(x)C(y) (x>1, y>0). The spin reorientat ion temperature, T-sr, was influenced by both carbon interstitial and Ga or Al substitution for Fe and ascribed to the increase of the c-axi s uniaxial anisotropy of the Er3+ sublattice by the modification of el ectron structure around it. The highest T-sr of 241 K appears in the c ompound Er2Fe14Ga3C. (C) 1996 American Institute of Physics.