High-Field Magnetization Study of R₂Fe₁₇H₃ (R = Tb, Dy, Ho and Er) Single-Crystalline Hydrides

The high-field magnetization process in the hydrogen-charged R₂Fe₁₇H₃ (R = Tb, Dy, Ho and Er) single crystals is studied along principal crystallographic directions at T = 4.2 K and compared with that of the known parent R₂Fe₁₇ compounds. Substantial changes of the magnetic anisotropy behavior induced by hydrogenation are found. Depending on the rare earth atom, the R₂Fe₁₇H₃ compounds possess the "easy-axes", "easy-cone" and "easy-plane" types of magnetocrystalline anisotropy (MCA), whereas the precursors R₂Fe₁₇ have the easy-plane type of MCA only. The various observed types of the field-induced phase transitions in R₂Fe₁₇H₃ are discussed and information on the effect of hydrogen on the strength of R-Fe coupling is obtained.