ELECTRONIC AND STRUCTURAL STUDIES OF THE HYDRIDES OF ErFe2 FROM 5 7Fe AND, 6 6Er MOSSBAUER SPECTROSCOPY"1"

Abstract.- Two different hydrides of the C15 Laves phase intermetallic ErFe2 are considered. For ErFe2H3.es, X-ray analyses showed the presence of an expanded C15 cubic phase and a lower symmetry phase. The 57Fe mean saturated hyperfine field is 20 % larger than in ErFe2 and the 166Er hyperfine field is 15 % smaller. These results coupled with previous measurements of the net moment imply that the Er-Fe coupling is not antiparallel in this hydride. For ErFe2Hit.i2, the only phase detected was rhombohedral. The Mossbauer results indicate a magnetic transition temperature between 1.7 K and 4.2 K and a drastic reduction of the Fe moment in this hydride. 1. Introduction.- Many rare-earth 3d transition me-tal intermetallic compounds readily absorb large quantities of hydrogen /1,2/. The hydrogen capacity of these systems is thought to be closely related to their structural and electronic properties. A favo