Theory of Knight Shift and Spin-Lattice Relaxation Rates of Pu-115

摘要

We calculated the Knight shift and spin-lattice relaxation rates of Pu-115compounds assuming d-wave superconductivity in the presence of strong impurityscattering. We discuss the implications for recent measurements of thespin-lattice relaxation rate in the Pu-115 compound PuRhGa5 by Sakai andcoworkers [J. Phys. Soc. Jpn. 74, 1710 (2005)] and present a prediction for thecorresponding Knight shift. In addition, we noticed a significant round-off ofthe spin-lattice relaxation rate 1/T1 just above the superconducting transitiontemperature that is not observed in the sister compound PuCoGa5. It appearsthat in PuRhGa5 superconductivity is mediated by spin fluctuations, too. Thisprovides additional support to the scenario of superconducting pairing mediatedby spin fluctuations in the Pu-115 compounds similar to the Ce-115 compoundsand the high-temperature copper-oxide superconductors.