Coexistence of antiferromagnetic order and unconventional superconductivity in heavy-fermion CeRh1−xIrxIn5 compounds: Nuclear quadrupole resonance studies

Abstract

We present a systematic In115 NQR study on the heavy-fermion compounds CeRh1−xIrxIn5 (x=0.25, 0.35, 0.45, 0.5, 0.55, and 0.75). The results provide strong evidence for the microscopic coexistence of antiferromagnetic (AF) order and superconductivity (SC) in the range of 0.35⩽x⩽0.55. Specifically, for x=0.5, TN is observed at 3K with a subsequent onset of superconductivity at Tc=0.9K. Tc reaches a maximum (0.94K) at x=0.45 where TN is found to be the highest (4.0K). Detailed analysis of the measured spectra indicate that the same electrons participate in both SC and AF order. The nuclear spin-lattice relaxation rate 1∕T1 shows a broad peak at TN and follows a T3 variation below Tc, the latter property indicating unconventional SC as in CeIrIn5 (Tc=0.4K). We further find that, in the coexistence region, the T3 dependence of 1∕T1 is replaced by a T-linear variation below T∼0.4K, with the value (T1)Tc∕(T1)lowT increasing with decreasing x, likely due to low-lying magnetic excitations associated with the coexisting magnetism.

Source-reported materials — not catalogue approval

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