The orientation dependence of the hydrogen distribution within Mo/V (110) and (001) multilayered artificial superlattices

We have investigated the hydrogen distribution within multilayered Mo/V (110) and (001) artificial superlattices. The hydrogen concentration, determined by the 1H(15N, αγ)12C nuclear resonance reaction, is found to decrease with decreasing layer thickness. The decrease is attributed to an interface region with reduced hydrogen content. The extension of this interface region is found to be two monolayers in Mo/V (110), compared to the previously reported three monolayers in Mo/V (001) superlattices. In the (110) oriented samples the relative amount of H in the interface region decreases with increasing average H content (H/V (atomicratio) approx. 0.3-0.5). This effect is shown to be related to the orientation of the hydrogen planes with respect to the boundaries implied by the Mo/V interfaces. The hydrogen induced volume change, obtained by conventional θ-2θ x-ray diffraction (XRD) and reciprocal space mapping, is found to be smaller for the (110) samples than for the (001) oriented samples at room temperature. (author)