Abstract
Intermetallic compounds based on rare-earth metals and iron are by far the most promising materials for permanent magnets. In this work, the multicomponent compound Sm1.2Ho0.8Fe17 was prepared by induction melting.
The hydride Sm1.2Ho0.8Fe17H4.4 with a high hydrogen content was obtained by direct hydrogenation of the intermetallic compound. The rhombohedral Th2Zn17-type of structure (space group R (3) over barm) is inherent to parent compound and hydride as well.
The effect of hydrogenation on the magnetic properties of Sm1.2Ho0.8Fe17 was investigated. Curie temperature of the hydride Sm1.2Ho0.8-Fe17H4.4 is higher than that of parent compound by Delta T-C = 138 K.
The hydrogen embedded in Sm1.2Ho0.8Fe17 crystal lattice increases the saturation magnetization (sigma(S)) at T = 300 K, but does not significantly affect sigma(S) 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-reorientation phase transition observed at 55 T.
It is found that the parameter of the intersublattice exchange interaction decreases significantly in the hydride Sm1.2Ho0.8Fe17H4.4 (and in the nitride Sm1.2Ho0.8Fe17N2.4) which is associated with boosting of the unit-cell volume and distances between magnetic ions. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V.
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