Synthesis,structure and magnetic properties of Sm_(1.2)Ho_(0.8)Fe_(17)Hx(X=0;4.4)

Intermetallic compounds based on rare-earth metals and iron are by far the most promising materials for permanent mag nets.In this work,the multicomponent compound Sm_(1.2)Ho_(0.8)Fe_(17)was prepared by in duction melting.The hydride Sm_(1.2)Ho_(0.8)Fe_(17)H_(4.4)with a high hydrogen content was obtained by direct hydrogenation of the intermetallic compound.The rhombohedral Th2Zn17-type of structure(space group R3^(-)m)is inhere nt to parent compound and hydride as well.The effect of hydrogenation on the magneric properties of Sm_(1.2)Ho_(0.8)Fe_(17)was investigated.Curie temperature of the hydride Sm_(1.2)Ho_(0.8)-Fe_(17)H_(4.4)is higher than that of parent compound by△Tc=138 K.The hydrogen embedded in Sm_(1.2)Ho_(0.8)Fe_(17)crystal lattice in creases the saturation magnetization(σs)at T=300 K,but does not significantly affect%at T=4.2 K.The ferrimagnetic structure is retained in magnetic fields up to 58 T in the parent compound,while,in the hydride,there is a spin-reorie ntatio n phase transitio n observed at 55 T.It is found that the parameter of the in tersublattice exchange interaction decreases significantly in the hydride Sm_(1.2)Ho_(0.8)Fe_(17)Hg_(4.4)(and in the nitride Sm_(1.2)Ho_(0.8)Fe_(17)N_(2.4))which is associated with boosting of the unit-cell volume and distances between magnetic ions.