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

TL;DR

This paper models the Knight shift and spin-lattice relaxation rates in Pu-115 superconductors assuming d-wave pairing, linking experimental observations to spin fluctuation-mediated superconductivity.

Contribution

It provides theoretical calculations of relaxation rates and Knight shift in Pu-115 compounds, supporting spin fluctuation-mediated pairing mechanisms.

Findings

Calculated relaxation rates and Knight shift for Pu-115 compounds.

Predicted Knight shift behavior near the superconducting transition.

Identified differences in relaxation rate behavior between PuRhGa5 and PuCoGa5.

Abstract

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