Pressure-induced change of the antiferromagnetic structure in CeRhIn 5 studied by In-NQR measurements

Abstract

We report a pressure-induced evolution of magnetism and superconductivity in a helical magnet CeRhIn5 with an incommensurate wave vector Q i = (1/2 , 1/2 , 0.297) through the 115In nuclear quadrupole resonance (NQR) measurements under P. From systematic measurements of the 115In- NQR spectrum, it is suggested that the commensurate antiferromagnetic order with Qc = (1/2 , 1/2 , 1/2 ) is realized near an antiferromagentic quantum critical point. The homogeneous coexistence of superconductivity and the commensurate antiferromagnetism is observed from the measurements of a nuclear spin-lattice relaxation rates (1/T1) at 1.82 GPa. The analysis for 1/T1 data below Tc indicates that the strong coupling superconductivity is realized above an antiferromagnetic quantum critical point. © 2012 The Physical Society of Japan.