Heavy Fermion Superconductor Ce2pdin8 Studied By In-115 Nuclear Quadrupole Resonance

We have performed nuclear quadrupole resonance (NQR) measurements on a recently-discovered heavy-fermion superconductor Ce2PdIn8 with superconducting critical temperature T-c = 0.64 K. Below coherent temperature T-coh similar to 30 K, the spin-lattice relaxation rate 1/T-1 decreases with decreasing temperature T and is proportional to T-1/2 between T-c and T-coh. This is clearly different from the Fermi-liquid behavior in which the T dependence is proportional to T, and indicates that Ce2PdIn8 is located on the verge of antiferromagnetic quantum critical point from the view point of the NQR. Below T-c, 1/T-1 shows no coherence peak and is proportional to T-3. This is clear evidence for the realization of unconventional superconductivity with line nodes in this compound.