Novel phase diagram of antiferromagnetism and superconductivity in CeRhIn5

We report on the pressure (P)-induced phase diagram of antiferromagnetism (AFM) and superconductivity (SC) which emerges at their border at zero magnetic. field. The nuclear-quadrupole- resonance (NQR) measurements have revealed that AFM can take place in the superconducting state with Tc similar to 2.1K at P 2.05 GPa. The present experiments have, for the. first time, demonstrated that AFM phase, AFM + SC uniformly coexisting phase, SC phase and paramagnetic phase all contact with each other at T-tetra similar to 2.1K and Ptetra similar to 2GPa which evidence the existence of the tetracritical point in the P-T phase diagram of AFM and SC in CeRnIn5. (c) 2006 Elsevier B.V. All rights reserved.