Magnetic interface polarization of the La-5d states in Fe/LaHx multilayers

For rare-earth (RE)-hydrides (REHx), a metalto-insulator transition is obse rved if the hydrogen concentration is increased from the dihydride (x = 2) towards the trihydride (x = 3). This transition provides an object for stud ies of the magnetic interface polarization in layered ferromagnet/insulator structures. For different samples with a fixed Fe and varied LaHx sublayer thickness t(LaHx) ([15 Angstrom Fe/t Angstrom LaHx]xn), the H concentratio n x in the LaHx sublayer is gradually increased in the experiment. Starting from the as prepared dihydride REH2-8, the modification of the magnetic po larization of the La-5d states at the Fe/La-x., interface is studied across the transition by magnetic circular dichroism measurements at the La-L-2 a nd L-3 edges. The experiments reveal an induced magnetic polarization of th e La-5d hole states on a length scale of 9 Angstrom that is independent of the altered electronic structure of the La-5d states.