MOMENT FORMATION UPON HYDROGEN ABSORPTION IN HF2FE

The cubic intermetallic compound Hf2Fe can absorb large quantities of hydrogen gas without changing its crystal structure (Ti2Ni type). Whereas the Fe atoms do not have a moment in Hf2Fe we measured a moment of about 0.9 uB per Fe atom in the hydride Hf2FeH3. The ferromagnetic Curie temperature of Hf2FeH3 is Tc = 73 K. Using 57Fe Mössbauer effect spectroscopy we found that the isomer shift changes +0.40 mms-1 upon H2 take-up. This isomer shift change is not compatible with an explanation of the observed moment increase in terms of charge transfer from Fe to H. © 1979.