Effect of pressure on spin fluctuations and superconductivity in heavy-fermionUPt3

Abstract

We have determined the effect of hydrostatic pressure on the susceptibility, on the $T^2$ temperature dependence of the spin-fluctuation resistivity, and on superconductivity in ${\mathrm{UPt}}_3$. The spin-fluctuation temperature $T_s$, derived from the slope of resistivity versus $T^2$, is used within a Fermi-liquid picture to calculate the susceptibility χ at T=0 K. The depression of this calculated χ with pressure agrees with the directly measured value ∂ lnχ/∂P=-24 ${\mathrm{Mbar}}^{\mathrm{-}1}$. Both the superconducting transition temperature $T_c$ and the initial slope of the upper critical field also decrease under pressure. We find that ∂ ln$T_c$/∂P=-25 ${\mathrm{Mbar}}^{\mathrm{-}1}$ and speculate upon correlations between χ and $T_c$.