2011/03/31 by Long Ma, G. F. Ji, Jia Dai +8 · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Computer science #Inorganic Chemistry and Materials #Iron-based superconductors research #Physics #Rare-earth and actinide compounds #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.84.220505
published as Phys. Rev. B 84, 220505(R) (2011)
openalex publication_date 2011/12/22 · arxiv created 2011/12/27 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report nuclear magnetic resonance (NMR) studies of the intercalated iron selenide superconductor (Tl,Rb)yFe_2\ensuremath-xSe2 (Tc=32 K). Single-crystal measurements up to 480 K on both 77Se and 87Rb nuclei show a superconducting phase with no magnetic order. The Knight shifts K and relaxation rates 1/T1T increase very strongly with temperature above Tc, before flattening at 400 K. The quadratic T-dependence and perfect proportionality of both K and 1/T1T data demonstrate their origin in paramagnetic moments. A minimal model for this pseudogap-type response is not a missing density of states, but rather two additive contributions from the itinerant electronic and local magnetic components, a framework unifying the K and 1/T1T data in many iron-based superconductors.