Magnetic Properties of Superconducting Mo-Re Alloys

This paper gives details of research carried out on the low-temperature properties of Mo-Re alloys in the superconducting state. Measurements were made on a 52-48% alloy of Mo-Re both unannealed and annealed, the alloy being in the form of fine wires. Micrograph studies were made to determine the percentage of the various phases present in each specimen. The low-temperature measurements covered observations of the magnetization as a function of applied magnetic field at various temperatures using two different techniques. The measurements yielded the critical magnetic fields $H_{c1\mathrm{}}$ and $H_{c2\mathrm{}}$ as a function of temperature and of the state of anneal, as well as of the transition temperature $T_c$. Estimates were made of $H_c\mathrm{}\left(T\right)\mathrm{}$ and the Ginzburg-Landau-Abrikosov-Gor'kov and Maki parameters $\kappa$, ${\kappa }_1\mathrm{}\left(T\right)\mathrm{}$, and ${\kappa }_3\mathrm{}\left(T\right)\mathrm{}$. Comparisons of the results are made with results obtained previously by us from resistivity measurements on the same alloy and by other authors on similar superconducting alloys; the comparisons show consistency in the data. Our evaluations of $\frac{{\kappa }_1\mathrm{}\left(T\right)\mathrm{}}{{\kappa }_1\left(T_c\right)}$ and of $\frac{{\kappa }_3\mathrm{}\left(T\right)\mathrm{}}{{\kappa }_3\left(T_c\right)}$ are consistent with the theory of Maki.