Magnetic and Superconducting Properties of CeRhGe2 and CePtSi2

We synthesized a new compound of CeRhGe 2 with the orthorhombic CeNiSi 2 -type structure. By measuring the electrical resistivity, magnetic susceptibility, magnetization, specific heat, and neutron scattering for single crystals, CeRhGe 2 was found to order antiferromagnetically below T N = 7.6 K with an ordered moment of 1.3 µ B /Ce oriented along the magnetic easy-axis of the c -axis. Similar measurements were also carried out for CePtSi 2 single crystals. From the experimental results of anisotropic magnetic susceptibility and magnetization, the crystalline electric field (CEF) scheme was obtained for CeRhGe 2 and CePtSi 2 , together with the similar compound CeNiGe 2 . Furthermore, we carried out pressure experiments by measuring the electrical resistivity of CePtSi 2 and CeRhGe 2 . In the quantum critical region where the Neel temperature becomes zero, we observed superconductivity in CePtSi 2 and most likely CeRhGe 2 , at 1.5 and 7.1 GPa, respectively. The upper critical field of CePtSi 2 was found ...