Pressure-induced superconductivity in UIr without inversion symmetry

Pressure-induced superconductivity is found in UIr without inversion symmetry. The pressure–temperature phase diagram has been investigated by means of electrical resistivity and magnetization. The phase diagram consists of two ferromagnetic phases. The ferromagnetic phase FM1 with T C 1 ∼ 46 K at ambient pressure disappears around 1.7 GPa. With further increase of pressure, the phase (FM2) with small ferromagnetic moment appears in the pressure range of P C 1 P 2.6 GPa . The superconducting phase exists near the disappearance point of the FM2 phase, indicating that the superconductivity is associated with the ferromagnetic critical fluctuation around P C 2 .