The phase diagram of antiferromagnetism and superconductivity in CeRhIn₅: a study of ¹¹⁵In NQR under pressure

We report on the pressure (P) versus temperature (T) phase diagram of the P-induced heavy fermion (HF) superconductor CeRhIn5 via nuclear quadrupole resonance (NQR) measurements under P. At P = 2.1 GPa, the T dependence of the nuclear spin-lattice relaxation rate 1/T-1 revealed antiferromagnetic critical fluctuations due to the closeness of antiferromagnetism. As P decreases slightly down to 1.9 GPa, a pseudogap emerges above T-c similar to 2 K, suggesting the appearance of superconducting fluctuations associated with a strong coupling effect among quasiparticles.