Single Crystal Growth of and Hyperfine Couplings in the Spin-Triplet Superconductor K2Cr3As3

We report single crystal growth of the spin-triplet superconductor K2Cr3As3 with superconducting transition temperature Tc = 6.2 K, and the measurements of magnetic susceptibility chi as well as the Knight shift above Tc. We determined the hyperfine coupling constants directly from the relation between the Knight shift (K) and susceptibility (K-chi plot) and obtained the orbital contribution Korb. Our results of Korb is in fairly good agreement with the previous estimate by a novel method. Using the obtained parameters, we calculated the spin susceptibility chi s, which is found to be isotropic above Tc, in spite of a quasi-one dimensional crystal structure.