Аннотация:http://dx.doi.org/10.1016/j.jsamd.2016.05.001
Crystal structure and magnetic properties were studied on a single crystal of HoFe6Al6H and compared with those of the parent HoFe6Al6compound with a tetragonal crystal structure of the ThMn12 type.Hydrogenation leads to a 1% volume expansion. HoFe6Al6 is a ferrimagnet with exact compensation of the Ho and Fe sublattices magnetizations at low temperatures. Both the hydride and the parent compound display a high magnetic anisotropy of the easy-plane type, a noticeable anisotropy exists also within the easy plane with the [110] axis as the easy magnetization direction. The hydrogenation increases slightly (from 10 to 10.45 mB) the magnetic moment of the Fe sublattice as a result of volume
expansion. It leads to a decompensation of the Fe and Ho sublattices and HoFe6Al6H has a spontaneous moment 0.45 mB/f.u. The enhancement of the Fe-Fe intra-sublattice exchange interaction results in a higher Curie temperature (TC) value, 350 K in the hydride as compared to 315 K of HoFe6Al6. The Ho-Fe inter-sublattice interaction is also enhanced in the hydride. The molecular field Hmolcreated on Ho ionsby Fe sublattice is 38 T in HoFe6Al6
and 48 T in HoFe6Al6H. The inter-sublattice exchange constant Ho-Fe is 3.8 T/mB and 4.6 T/mB, respectively. High-field measurements confirm the enhancement of the Ho-Fe
exchange interaction in the hydride found from the temperature dependence of magnetization.