Superconductivity in heavy-fermionCeRh2Si2

We report the discovery of a superconducting transition in the heavy-fermion compound ${\mathrm{CeRh}}_2$ ${\mathrm{Si}}_2$ under hydrostatic pressure. Superconductivity appears at pressures above about 9 kbar, near the critical pressure required to suppress antiferromagnetic order [${\mathit{T}}_{\mathit{N}}$(P=0)=36 K]. Onset of superconductivity occurs at a temperature of ≊350 mK. Resistivity measurements as a function of field at constant temperature allow us to build an ${\mathit{H}}^{\mathrm{*}}$-T phase diagram for the onset of superconductivity. A Ginzburg-Landau analysis of the initial slope of the critical field leads to an effective mass of ${\mathit{m}}^{\mathrm{*}}$/${\mathit{m}}_0$≊200, supporting the heavy-fermion nature of superconductivity in ${\mathrm{CeRh}}_2$ ${\mathrm{Si}}_2$. Magnetic ac susceptibility (${\mathrm{\chi }}_{\mathrm{ac}}$) shows a diamagnetic response corresponding to about 1% of perfect diamagnetism. The size of the feature in ${\mathrm{\chi }}_{\mathrm{ac}}$ also is strongly peaked at a pressure of ≊9 kbar. © 1996 The American Physical Society.