Competing ordered phases in URu2Si2: hydrostatic pressure and rhenium substitution.
A persistent kink in the pressure dependence of the "hidden order" (HO) transition temperature of URu(2-x)RexSi2 is observed at a critical pressure P(c)=15 kbar for 0 <or= x <or= 0.08. In URu2Si2, the kink at P(c) is accompanied by the destruction of superconductivity, a change in the magnitude of a spin excitation gap, determined from electrical resistivity measurements; and a complete gapping of a portion of the Fermi surface (FS), inferred from a change in scattering and the competition between the HO state and superconductivity for FS fraction.