57Fe Mouml;ssbauer effect in ThFe5hydride

摘要

The hydrogen absorption in the CaCu5hyphen;type compound ThFe5was studied by xhyphen;ray diffraction, magnetic measurements, and57Fe Mouml;ssbauer spectroscopy. Hydrogen absorption leads to a 6percnt; increase of the unit cell volume without change in crystal structure. There is only a slight change in magnetic properties. The57Fe Mouml;ssbauer spectra of the ternary hydride are characterized by relatively sharp lines, an increase in hyperfine field, and an increase in isomer shift relative to the uncharged compound. The increase in57Fe isomer shift invariably observed after charging of Fe compounds with hydrogen is explained in terms of the Miedemandash;van der Woude model. The relatively low tendency of the hydride of ThFe5to decompose (disproportionate) as compared to some other Thhyphen;Fe hydrides is explained on the basis of a kinetic approach.