Localization, magnetism, and superconductivity in two-dimensional Pd1−yNiyHx films

Abstract

Through localization studies we measure the spin-flip and the inelastic electron-electron scattering rates ${\tau }_S^{\mathrm{-}1}$ and ${\tau }_{\mathrm{ee}}^{\mathrm{-}1}$ in ${\mathrm{Pd}}_{1\mathrm{-}\mathrm{y}}$ ${\mathrm{Ni}}_{\mathrm{y}}$ ${\mathrm{H}}_{\mathrm{x}}$ two-dimensional films, a system which appears to be nearly magnetic. A strong increase of ${\tau }_{\mathrm{ee}}^{\mathrm{-}1}$, in comparison with pure PdH, is observed for the saturated (x∼1) samples. A decrease of x leads to a further increase of ${\tau }_{\mathrm{ee}}^{\mathrm{-}1}$ as well as to a marked increase of ${\tau }_S^{\mathrm{-}1}$. We relate these effects to the growth of magnetic fluctuations on either isolated Ni atoms or on small Ni clusters. These results can also explain the decrease with Ni content of the superconducting $T_c$ in bulk and thin films of Pd-Ni-H.