The question of whether the application of sufficient pressure can destroy superconductivity completely is considered for the superconductors Al, Cd, Zn, In, Sn, and Pb. The superconducting transition temperature $T_c$ for these elements is found to vary linearly with volume over an appreciable range of volume. Extrapolation to $T_c=0\mathrm{}$ yields critical pressures of 67, 38, and 41 kbar for the destruction of superconductivity in Al, Cd, and Zn, respectively. These values are compared with considerably higher estimates obtained in previous analyses. Measurements of $T_c$ for lead, as a function of pressure up to a maximum pressure of 30 kbar, are presented. On combining these data with Bridgman's room-temperature compressibility measurements for lead, $T_c$ is found to vary linearly with volume and $\frac{\partial T_c}{\partial V}=0.907\mathrm{}{}_{}{}^{\circ }{}_{}{}^{}\mathrm{K}$ ${\mathrm{cm}}^{-3\mathrm{}}$, corresponding to $\frac{\partial T_c}{\partial P}=-3.86\mathrm{}\pm 0.12\times {10}^{-5\mathrm{}}{}_{}{}^{\circ }{}_{}{}^{}\mathrm{K} {\mathrm{bar}}^{-1\mathrm{}}$ at $P=0\mathrm{}$.

• Received 1 January 1967

DOI:https://doi.org/10.1103/PhysRev.159.353