115 In -NQR evidence for unconventional superconductivity in CeIn 3 under pressure

We report evidence for unconventional superconductivity in ${\mathrm{CeIn}}_{3}$ at a pressure $P=2.65 \mathrm{GPa}$ above the critical pressure ${(P}_{c}\ensuremath{\sim}2.5 \mathrm{GPa})$ revealed by measurements of the nuclear-spin-lattice-relaxation time ${(T}_{1})$ and ac susceptibility (ac-$\ensuremath{\chi}).$ Both measurements of ${T}_{1}$ and ac-$\ensuremath{\chi}$ have pointed to a superconducting transition at ${T}_{c}=95 \mathrm{mK},$ which is much lower than the onset temperature ${T}_{\mathrm{onset}}=0.15 \mathrm{K}$ 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 ${\mathrm{CeIn}}_{3}.$