Properties of Superconducting Lead-Indium Alloys and the Generalized Ginzburg-Landau Parameter<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>κ</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Magnetization measurements have been made on a series of lead-indium alloys containing from 5 to 60 at.% indium. The upper and lower critical fields together with the generalized Ginzburg-Landau parameter ${\ensuremath{\kappa}}_{2}$ have been obtained at temperatures between $0.2{T}_{c}$ and ${T}_{c}$. Residual resistivities and transition temperatures have also been measured. It is found that ${\ensuremath{\kappa}}_{2}$ increases with decreasing temperature, the magnitude of the increase being much higher than that expected from existing theory. However, the increase as a function of the Gor'kov impurity parameter $\ensuremath{\rho}$ closely follows available data for niobium alloys. This result lends support to the view that, despite the present conflict between experiment and theory, an experimental parameter ${\ensuremath{\kappa}}_{2}(\ensuremath{\rho}, T)$ does exist which is independent of the detailed characteristics of the alloy system being investigated. Temperature-independent characteristics of the lead-indium system are collected together, and some evidence is found for a modification of the electronic structure at an indium concentration of about 30 at.%.

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