Resonance Impurity Scattering in PrOs₄Sb₁₂

We study the effect of impurity scattering in the unitarity limit on the A and B phase superconductivity in PrOs4Sb12. We take the triplet superconducting order parameters and the impurity scattering is treated within the standard theory. We find the quasiparticle density of states and thermodynamics are very sensitive to the impurity scattering. The impurity scattering dependence of the superconducting transition temperature and the order parameter at T=0 are very similar to those in d-wave superconductors. Some of these characteristics will provide a sensitive test of the symmetry of the underlying order parameters.