Magnetic and magnetoelastic properties of amorphous and crystalline TbFe2Hx hydrides

The crystal structure, magnetic and magnetoelastic properties of TbFe 2 H x hydrides (x ⩽ 4.2), amorphous TbFe 2 H 2.5 hydride and amorphous TbFe 2 obtained by mechanical grinding have been investigated. It is established that the structure of atomic short-range order in the amorphous hydride is quite different from that in the mechanically ground sample. Both the introduction of hydrogen and amorphization is shown to cause a decrease in the magnetic moment and the magnetostriction, and a weakening of Tb-Fe and Fe-Fe exchange interactions. The changes in the magnetic properties of the samples are interpreted in terms of a supposition of random anisotropy and non-collinear magnetic structure in the Tb sublattice.