On the breakdown of the iron sublattice long-range magnetic order in RFeAl hydrides (R ≡ rare earth)

Abstract

In the cubic C15 type Laves phase compounds RFe 2 (R ≡ rare earth), hydrogen absorption commonly leads to a rise in the moment on the iron site. If, however, half the iron is substituted by the non-magnetic aluminium, a remarkable weakening of the magnetic order is found for the resulting hexagonal C14 RFeAl hydrides. Distinct peaks in the initial susceptibility vs. temperature curve indicate the occurrence of magnetic order of the short-range type. In certain cases, where ferromagnetism is preserved in the hydrides, 57Fe Mössbauer spectra indicate that even here a substantial number of iron atoms have lost their moments upon charging.