Anisotropic Residual Resistivity Under High Pressure in UIr

Anisotropic resistivity in UIr has been investigated under high pressure. A huge enhancement of residual resistivity was found under high pressure for the measuring current parallel to the [0 1 0] direction while any anomalies were not observed in the resistivity for [1 0 1 ]. The residual resistivity for [0 1 0] reduced to the original value in the pressure range where superconductivity appears. This anomalous behavior indicates that the ground state in the high-ρ 0 state is not simple ferromagnet and the application of pressure induces the first-order transition to slightly different electronic state.