Magnetic properties of Y_(0.7)Er_(0.3)Fe_2(H, D)_(4.2) compounds under continuous magnetic field up to 35 tesla

摘要

The study of the Y_(0.7)Er_(0.3)Fe_2(H,D)_(4.2) shows that the Y for Er substitution modifies both structural and magnetic properties of the hydrides and deuterides. Their cell volume is smaller than for the nonsubstituted compounds. Under high magnetic field two field-induced transitions are observed, the first one that takes place between 4.2 and 26 K (hydride) and 53 K (deuteride) originates from the erbium magnetic behavior, the second one found above 101 K (hydride) and 60 K (deuteride) is mainly attributed to an antiferro-ferromagnetic transition in the Fe sublattice. This important isotopic effect is attributed to the change of the cell volume induced by the deuterium and hydrogen insertion. Comparison with YFe_2H_(4.2) and YFe_2D_(4.2) compounds shows that the temperature at which appears the second transition is shifted to lower values. The transition field increases linearly versus temperature but with a much larger ΔH_(TR)/ΔT slope for the deuteride compared to the hydride whereas there were similar in the nonsubstituted compounds. The roles of both cell volume change and erbium magnetic contribution are briefly discussed.