Hydrogen-charging of Nb/Fe multilayers

Nb/Fe multilayers with a Pd top layer were prepared by electron beam evaporation on Si substrates. The multilayer stacks were charged with hydrogen from the gas phase at 200 degrees C and at a gas pressure of 0.1 mbar. The resulting hydrogen concentration profiles were measured by the N-15 nuclear reaction method. We find that the multilayers take up hydrogen under these conditions, that hydrogen also reaches the low lying layers and that hydrogen is accumulated in Nb, leaving the Fe layers essentially hydrogen-free. The present work was undertaken as a preparatory study for the investigation of the magnetic coupling of the Fe layers through the Nb spacers as a function of the hydrogen content.