We report a study on the interplay between antiferromagnetism (AFM) and superconductivity (SC) in a heavy-fermion compound ${\mathrm{C}\mathrm{e}\mathrm{R}\mathrm{h}\mathrm{I}\mathrm{n}}_5$ under pressure $P=1.75\mathrm{G}\mathrm{P}\mathrm{a}$. The onset of the magnetic order is evidenced from a clear split of ${}^{115}\mathrm{I}\mathrm{n}$ nuclear quadrupole resonance spectrum due to the spontaneous internal field below the Néel temperature $T_N=2.5\mathrm{K}$. Simultaneously, bulk SC below $T_c=2.0\mathrm{K}$ is demonstrated by the observation of the Meissner diamagnetism signal whose size is the same as in the exclusively superconducting phase. These results indicate that the AFM coexists homogeneously with the SC at a microscopic level.

• Received 14 April 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.077004