Evolution of the magnetism and superconductivity in CeRhIn₅ under pressure: ¹¹⁵In-NQR study

We report a novel pressure(P)-induced evolution on the magnetism in the P-induced superconductor CeRhlns revealed by measurements of the ¹¹⁵ In nuclear-spin-lattice-relaxation rate (¹¹⁵1/Ti). In the itinerant antiferromagnet CeRhln₅ with the Néel temperature Tn = 3.8 K at P=0, Tn begins to be reduced to Tn = 3.6 K at P = 1.23 GPa that is close to the border of the superconducting phase. An emergent behavior is the observation of a pseudogap behavior that is revealed by a broad peak in the temperature dependence of 1/T₁T at P = 1.23 GPa. With further increasing P up to P = 2.1 GPa where its bulk superconductivity is fully established, the pseudogap behavior is not seen in the normal state. The insensitive P dependence of T_c in CeRhln₅ is suggested to be related to that of the characteristic temperature T which marks a localized to itinerant magnetic crossover.