Origin of the metamagnetic transitions in Y1−Er Fe2(H,D)4.2 compounds

V. Paul-Boncour (1) , O. Isnard (2) , V. Shtender (1) , Y. Skourski (3) , M. Guillot (4)

1 ICMPE - Institut de Chimie et des Matériaux Paris-Est
2 NEEL - MRS - Matériaux, Rayonnements, Structure
3 Dresden High Magnetic Field Laboratory
4 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble

The structural and magnetic properties of Y1−xErxFe2 intermetallic compounds and their hydrides and deuterides Y1−xErxFe2H(D)4.2 have been investigated using X-ray diffraction and magnetic measurements under static and pulsed magnetic field up to 60 T. The intermetallics crystallize in the C15 cubic structure (Fd-3m space group), whereas corresponding hydrides and deuterides crystallize in a monoclinic structure (Pc space group). All compounds display a linear decrease of the unit cell volume versus Er concentration; the hydrides have a 0.8% larger cell volume compared to the deuterides with same Er content. They are ferrimagnetic at low field and temperature with a compensation point at x=0.33 for the intermetallics and x=0.57 for the hydrides and deuterides. A sharp first order ferromagnetic-antiferromagnetic (FM-AFM) transition is observed upon heating at TFM−AFM for both hydrides and deuterides. These compounds show two different types of field induced transitions, which have different physical origin. At low temperature (T < 50 K), a forced ferri-ferromagnetic metamagnetic transition with Btrans1 ≈8 T, related to the change of the Er moments orientation from antiparallel to parallel Fe moment, is observed. Btrans1 is not sensitive to Er concentration, temperature and isotope effect. A second metamagnetic transition resulting from antiferromagnetic to ferrimagnetic state is also observed. The transition field Btrans2 increases linearly versus temperature and relates to the itinerant electron metamagnetic behavior of the Fe sublattice. An onset temperature TM0 is obtained by extrapolating TFM−AFM (B) at zero field. TM0 decreases linearly versus the Er content and is 45 ± 5 K higher for the hydrides compared to the corresponding deuteride. The evolution of TM0 versus cell volume shows that it cannot be attributed exclusively to a pure volume effect and that electronic effects should also be considered.

Mots clés: Laves Phases; Hydrides; Deuterides; Isotope effect; Metamagnetic transitions; High magnetic field; high magnetic field 2

Domaines: Matière Condensée [cond-mat]

V. Paul-Boncour, O. Isnard, V. Shtender, Y. Skourski, M. Guillot. Origin of the metamagnetic transitions in Y1−Er Fe2(H,D)4.2 compounds. Journal of Magnetism and Magnetic Materials, 2020, 512, pp.167018. ⟨10.1016/j.jmmm.2020.167018⟩. ⟨hal-02921583⟩