A study on the effect of hydrogen in the compounds with ThMn12-type structure

The structural and magnetic properties of hydrides with ThMn12-type structure have been studied by means of magnetic measurements, the neutron powder diffraction technique and self-consistent spin-polarized band calculations (LMTO-ASA). We found that the hydrides retain the ThMn12-type structure, but with an increase of unit-cell volume. The neutron diffraction results indicate that hydrogen atoms occupy the interstitial 2b sites. Magnetic measurements carried out on YFe10Mo2, YFe10.5Vx, YFe11Ti and their hydrides show that both the Curie temperature and the saturation magnetization can be enhanced by introducing interstitial hydrogen atoms. Band-structure calculations and spin-fluctuation theory give a fair description of the enhancement of the magnetization and Curie temperature.