Eur. Phys. J. B 18, 601-604 (2000)
https://doi.org/10.1007/PL00011077

Appearance of anisotropic non s-wave superconductivity above the critical pressure of antiferromagnetic CeRhIn₅

¹¹⁵In nuclear quadrupole resonance study

Department of Material Science, Faculty of Science, Himeji Institute of Technology, Kamigori-cho Ako-gun Hyogo 678-1297, Japan

Corresponding author: ^a kohori@sci.himeji-tech.ac.jp

Received: 5 July 2000
Published online: 15 December 2000

Abstract

We have carried out ¹¹⁵In nuclear quadrupole resonance (NQR) measurements in CeRhIn₅. At ambient pressure, CeRhIn₅ undergoes an antiferromagnetic AF phase transition at K. The ¹¹⁵In NQR spectrum has shown the appearance of a small internal field in the direction perpendicular to the tetragonal c-axis. With application of a hydrostatic pressure, the AF state is suppressed and the superconductivity appears just above the critical pressure (P = 17 kbar). The nuclear spin lattice relaxation rate 1/T₁ of ¹¹⁵In measured at P = 27 kbar indicates the occurrence of the superconductivity in the nearly AF region. In the superconducting state, 1/T₁ has no Hebel-Slichter coherence peak just below T_c of 2 K and has a power law T-dependence (T³) down to 300 mK. This is consistent with anisotropic superconductivity, with line nodes in the superconducting energy gap: non-s-wave superconductivity occurs in CeRhIn₅.