The Magnetic Properties of GdxY6−xFe23 (x = 0,1,2,3) Compounds and Their Hydrides

The magnetic properties of the compounds GdxY6−xFe23 (x = 0,1,2,3) and their hydrides were studied. In the parent intermetallics, progressive substitution of Gd in place of Y in Y6Fe23 led to a reduction in the magnetic moment (~ 7 μB per Gd substituted) and an increase in the Curie temperature. For the hydrided materials a similar effect was observed (Gd substitution into Y6Fe23H16 resulted in a decrease in magnetic moment and an increase in Curie temperature). In all cases the hydride exhibited a larger moment and a higher Curie temperature than the corresponding intermetallic. This behavior indicates that in both the parent compounds and the hydrides the Fe sublattice is dominant and antiparallel to the Gd sublattice. Furthermore, the Fe moment is increased by hydrogenation, which seems to indicate that hydrogen creates vacancies in the minority spin d-band (i.e., hydrogen behaves as an electron acceptor). All hydrides retained the crystal structure of the parent materials (Th6Mn23 type), with a volume expansion of about 11%.