Magnetic properties and 57Fe Mössbauer effect in Lu6Fe23 and Lu6Fe23H8

Hydrogen absorption in the cubic compound Lu₆Fe₂₃ ($\text{a}\text{= 11.936}\text{A}\text{?}$) leads to a ternary hydride of the composition Lu₆Fe₂₃H₈ ($\text{a}\text{= 12.072}\text{A}\text{?}$). The H₂ take-up causes a slight increase in the saturation magnetization corresponding to an increase in Fe moment from 1.54 /u_B to 1.64/u_B per atom. The hydrogen absorption did not lead to a substantial change in the linewidth of the ⁵⁷Fe Mössbauer spectrum. On the basis of the Mössbauer data it was inferred that the H atoms occupy the f-type interstitial holes characterized by a tetrahedron formed of three Lu atoms and one Fe atom. The decrease in hyperfine field upon charging was correlated with an increase in Curie temperature.