Superconducting Transition and Critical Field of Pure Gallium Single Crystals

Abstract

The superconducting critical temperature $T_c$ and critical-field curve for pure gallium have been measured using a ${\mathrm{He}}^3$ vapor-pressure thermometer. The critical field $H_c\mathrm{}\left(T\right)\mathrm{}$ has been measured in the temperature range 0.82-1.083°K. Within experimental error the results of the measurements can be expressed as $H_c\mathrm{}\left(T\right)=56.48\left[\right(1-t^2)-0.0314\mathrm{}sin\pi (1-t^2\left)\right]$, or $H_c\mathrm{}\left(T\right)=100.86\mathrm{}(1-t)-36.18\mathrm{}{\mathrm{}(1-t)\mathrm{}}^2$, or $(1-t^2)=\left(\frac{H_c}{57.807}\right)+0.0424\mathrm{}sin\left(\frac{\pi H_c}{57.807}\right)$, where $t=\frac{T}{T_c}$ and $T_c=1.0833\mathrm{}\pm 0.0005°$K.