Critical Magnetic Field and Transition Temperature of Synthetic High-Field Superconductors

Abstract

Measurements of the critical field $\hat{H}$ and transition temperature $\hat{T}$ of superconducting indium in porous glass have been made using a low-frequency mutual-inductance technique. The pore sizes of the glasses are well characterized, so that 96% of the pore volume is within ±10% of the mean pore diameter $d$. Pore diameters from 65 to 250 Å were used. Below $t \left(\equiv \frac{T}{\hat{T}}\right)=0.5\mathrm{}$, $\hat{H}$ can be represented approximately by $\hat{H}=\frac{(3415\mathrm{}\pm 40)(1-t^2)}{d^{(1.00\mathrm{}\pm 0.14)}},$