Pressure dependence of the critical magnetic field of superconducting lead

The pressure dependence of the critical magnetic field of lead has been measured in the range 0.3-4.2 K. The measurements were done using hydrostatic pressures up to 3 kbar. The pressure derivatives of H₀ and γ* are reported, where H₀ is the extrapolated critical magnetic field at 0 K and γ*=γV, where γ is the temperature coefficient of the normal electronic specific heat and V is the molar volume. ∂lnH₀∂lnV=4.77±0.12 and ∂lnγ*∂lnV=3.6±0.4. The shape of the experimental deviation function D(t)=h-(1-t²), where h=HH₀ and t=TTc, is shown to change under pressure, in agreement with the strong-coupling theory of superconducting lead under pressure.