Superconductivity and spin-glass like behavior in system with Pd sheet sandwiched between graphene sheets

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a superconducting transition at Tc (= 3.63±0.04 K). The superconductivity occurs in Pd sheets. The relaxation of MZFC (aging), which is common to spin glass systems, is also observed below Tc. The relaxation rate S(t) shows a peak at a characteristic time tcr, which is longer than a wait time tw. The irreversibility between χZFC and χFC occurs well above Tc. The susceptibility χFC obeys a CurieWeiss behavior with a negative Curie-Weiss temperature (−13.1 ≤ Θ ≤ −5.4 K). The growth of antiferromagnetic order is limited by the disordered nature of nanographites, forming spin glass-like behavior at low temperatures in graphene sheets. PACS numbers: 74.80.Dm, 75.30.Kz, 75.50.Ee, 72.15.Rn § [email protected] ‖ Juerg [email protected] Superconductivity and spin-glass like behavior in Pd-MG 2