Superconductivity and Electronic Properties of Mg-Cd and Some hcp Mg Alloys

The superconducting transition temperature ${T}_{c}$, electronic specific heat $\ensuremath{\gamma}$, and Debye temperature $\ensuremath{\Theta}$ have been measured in the Mg-Cd alloy system and in some other Mg-rich hcp alloys. No superconductivity could be detected in the latter above 0.013\ifmmode^\circ\else\textdegree\fi{}K. On the Cd-rich side of the Cd-Mg system ${T}_{c}$ drops rapidly on alloying with Mg, and if one correlates this with the drop in $\frac{c}{a}$, one may expect Mg to have ${T}_{c}$ around 1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$\ifmmode^\circ\else\textdegree\fi{}K. A subsidiary maximum in ${T}_{c}$ occurs at $x=0.20$ (in ${\mathrm{Mg}}_{x}{\mathrm{Cd}}_{1\ensuremath{-}x}$), where $\ensuremath{\gamma}$ and $\ensuremath{\Theta}$ have a marked maximum and minimum, respectively. At $x=0.50$, the $\ensuremath{\gamma}$ has a minimum and $\ensuremath{\Theta}$ has a maximum if the mass factor is divided out. The possible origin of the anomaly at $x=0.20$ is discussed in terms of ordering and an incipient instability reflected in the rapid variation of $\frac{c}{a}$.

Перевод пока недоступен