Anisotropy of upper critical field and surface superconducting state in the intermediate-valence superconductor CeIr3

${\mathrm{CeIr}}_{3}$ is a Ce-based superconductor with a superconducting transition temperature ${T}_{\mathrm{c}}=3.4$ K in an intermediate-valence state. We grew high-quality single crystals of ${\mathrm{CeIr}}_{3}$ using the Czochralski method, and measured the electrical resistivity, magnetic torque, and specific heat. The anisotropy of the superconducting upper critical field ${H}_{\mathrm{c}2}$ was determined. The temperature dependence of ${H}_{\mathrm{c}2}$, obtained from the resistivity measurements, suggests the multiband character of the superconductivity in ${\mathrm{CeIr}}_{3}$. Different field-angle dependencies of ${H}_{\mathrm{c}2}$ in electrical transport and thermodynamic measurements indicate the robust surface effect in the bulk superconductivity of ${\mathrm{CeIr}}_{3}$. We analyzed the surface superconductivity based on simple models to reveal the bulk superconducting properties. Our results support the isotropic bulk superconducting state and robust surface superconductivity in ${\mathrm{CeIr}}_{3}$ single crystals.