Effect of hydrogen on the interlayer exchange coupling in Fe/V superlattices

Electronic and magnetic structures of Fe/V superlattices with and without hydrogen in the vanadium spacer are investigated using a relativistic full-potential linear muffin-tin orbital method. We obtained short-range induced spin polarization in V as well as reduced Fe polarization at the Fe/V interface. The value of the magnetic moment induced on the vanadium atoms depends strongly on the distortion caused by the lattice mismatch and hydrogen loading whereas the total moment of the Fe and V interface layers remains almost unchanged. Hydrogenation of the V spacer leads to the decrease of the interface magnetic moment on the V atoms and to a reduction of the density of states (DOS) at the Fermi level. A low DOS could be one of the reasons for the experimental increase of the resistivity of the samples under hydrogen loading and leads to the disappearance of the antiferromagnetic exchange coupling in the Fe/(VH) superlattices for large hydrogen concentration. Doping the V film by a gold monolayer increases the DOS at the Fermi level and could recover the antiferromagnetic coupling.