^{115}In-NQR evidence for unconventional superconductivity in CeIn_3 under pressure

TL;DR

This study provides evidence of unconventional superconductivity in CeIn_3 under pressure, characterized by nuclear magnetic resonance and susceptibility measurements showing a transition at very low temperatures without a coherence peak.

Contribution

First demonstration of unconventional superconductivity in CeIn_3 under pressure using nuclear-spin-lattice-relaxation and ac-susceptibility measurements.

Findings

Superconducting transition at T_c = 95 mK under pressure

No coherence peak observed in 1/T_1 below T_c

Superconductivity induced in CeIn_3 is unconventional

Abstract

We report evidence for unconventional superconductivity in CeIn_3 at a pressure P = 2.65 GPa above critical pressure (P_c ~ 2.5 GPa) revealed by the measurements of nuclear-spin-lattice-relaxation time (T_1) and ac-susceptibility (ac-chi). Both the measurements of T_1 and ac-chi have pointed to a superconducting transition at T_c = 95 mK, which is much lower than an onset temperature T_{onset} = 0.15 K at zero resistance. The temperature dependence of 1/T_1 shows no coherence peak just below T_c, indicative of an unconventional nature for the superconductivity induced in CeIn_3.