Magnetic and Superconducting Properties of CeTX3 (T: Transition Metal and X: Si and Ge) with Non-centrosymmetric Crystal Structure

We grew single crystals of non-centrosymmetric compounds CeTSi 3 and CeTGe 3 (T: transition metal), and studied the magnetic properties by measuring the electrical resistivity, magnetic susceptibility and magnetization. We also studied the effect of pressure on the electronic states in antiferromagnets CeTGe 3 (T: Co, Rh, Ir) by measuring the resistivity under pressure. No noticeable change of the Neel temperature was observed up to 8 GPa in CeRhGe 3 and CeIrGe 3 , which are far from the magnetic quantum critical point. On the other hand, the Neel temperature in CeCoGe 3 was strongly decreased as a function of pressure, and pressure-induced superconductivity was observed in the pressure region from 5.4 GPa to about 7.5 GPa. The slope of upper critical field H c2 at 6.5 GPa is found to be extremely large, with an upturn curvature of H c2 with decreasing temperature: -d H c2 /d T = 200 kOe/K at the superconducting transition temperature T sc = 0.69 K, revealing unconventional superconductivity.