Pressure-induced superconductivity in CePd₅Al₂ and CeRhGe₂, new family of heavy fermion superconductors

Antiferromagnets CePd₅Al₂ and CeRhGe₂ with the quasi-two dimensional electronic state have been found to become superconductive by measuring the electrical resistivity under pressure. In these compounds, the Néel temperature decreases at high pressure and becomes approximately zero at critical pressure P_c = 9 GPa in CePd₅Al₂ and P_c = 7 GPa in CeRhGe₂. Superconductivity was observed around P_c. In CePd₅Al₂, the upper critical field H_c2 is found to be highly anisotropic among H||[001] and [100], reflecting nearly cylindrical Fermi surfaces along the tetragonal [001] direction.