Heavy Fermion Superconductor Ce2PdIn8 studied by 115In Nuclear Quadrupole Resonance

We have performed nuclear quadrupole resonance (NQR) measurements on a recently-discovered heavy-fermion superconductor Ce2PdIn8 with superconducting critical temperature Tc = 0.64 K. Below coherent temperature Tcoh ∼ 30 K, the spin-lattice relaxation rate 1/T1 decreases with decreasing temperature T and is proportional to T1/2 between Tc and Tcoh. 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 Tc, 1/T1 shows no coherence peak and is proportional to T3. This is clear evidence for the realization of unconventional superconductivity with line nodes in this compound