Coexistence of Antiferromagnetism and Superconductivity near the Quantum Criticality of the Heavy-Fermion Compound [Formula presented]

We report a study on the interplay between antiferromagnetism (AFM) and superconductivity (SC) in a heavy-fermion compound [Formula presented] under pressure [Formula presented]. The onset of the magnetic order is evidenced from a clear split of [Formula presented] nuclear quadrupole resonance spectrum due to the spontaneous internal field below the Néel temperature [Formula presented]. Simultaneously, bulk SC below [Formula presented] 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.