Ab initio calculations of L10 FePdH multilayered structure

• H in 2(FePd)nH (n = 1,2,3) reduces the magnetic moment of Fe and Pd.
• Reduction of Fe moment is H position dependent.
• Pd polarization is almost annihilated when H is in Pd and Fe layers.
• From phonons and elastic constants the structure with H is in Pd layer showed high anisotropies behavior.
• The shear strength of 2(FePd)2H in [100] (001) direction became much more important than in [100] (010) direction.

Using ab initio calculations, I fully describe the electronic, magnetic and elastic properties of mono equi-atomic multilayer of L10 FePd and FePdH where H belongs to one of the two layers or to both. I found that the magnetic polarization of palladium in FePd is almost annihilated when hydrogen is present in both atomic layers. On the other hand the reduction of Fe moment is hydrogen proximity dependant. From phonons calculations of the frequencies at the center of the Brillouin zone Γ(0; 0,0), I found an anomaly when hydrogen is only present in the palladium layer. Moreover, this late structure its calculated elastic constants did not follow the trend of variation present in the rest of studied structures. Also, from macroscopic bulk and shear elastic moduli its calculated anisotropies, point to considerable elastic anisotropies. My intuitive explanation, based on the electronic population of the 4d↑↓ and 3 d↑↓ orbitals of Pd and Fe respectively, is these values are a consequence of critical phase transition of Pd from magnetic to non magnetic state.