Local spin fluctuations in iron-based superconductors: 77Se and 87Rb NMR measurements of Tl0.47Rb0.34Fe1.63Se2

Abstract

We report nuclear magnetic resonance (NMR) studies of the intercalated iron selenide superconductor (Tl, Rb)${}_y$Fe${}_{2-x}$Se${}_2$ ($T_c=32$ K). Single-crystal measurements up to 480 K on both ${}^{77}$Se and ${}^{87}$Rb nuclei show a superconducting phase with no magnetic order. The Knight shifts $K$ and relaxation rates $1/T_{1}T$ increase very strongly with temperature above $T_c$, before flattening at 400 K. The quadratic $T$-dependence and perfect proportionality of both $K$ and $1/T_{1}T$ data demonstrate their origin in paramagnetic moments. A minimal model for this pseudogap-like response is not a missing density of states but two additive contributions from the itinerant electronic and local magnetic components, a framework unifying the $K$ and $1/T_{1}T$ data in many iron-based superconductors.

References in corpus (27)

• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Why Does Undoped FeSe Become A High Tc Superconductor Under Pressure?
• A Novel Large Moment Antiferromagnetic Order in K0.8Fe1.6Se2 Superconductor
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Evolution from Itinerant Antiferromagnet to Unconventional Superconductor with Fluorine Doping in La(O_{1-x}F_{x})FeAs Revealed by ^{75}As and ^{139}La Nuclear Magnetic Resonance
• Orbital-Selective Mott transition out of band degeneracy lifting
• Common Crystalline and Magnetic Structure of superconducting A2Fe4Se5
• Distinct Fermi Surface Topology and Nodeless Superconducting Gap in (Tl0.58Rb0.42)Fe1.72Se2 Superconductor
• Different resistivity response to spin density wave and superconductivity at 20 K in $C{a}_{1-x}N{a}_{x}F{e}_{2}A{s}_2$
• Coexistence of Magnetism and Superconductivity in the Iron-based Compound Cs_0.8(FeSe_0.98)_2
• Structural transition and anisotropic properties of single crystalline SrFe2As2
• The effect of varying Fe-content on transport properties of K intercalated iron selenide KxFe2-ySe2
• Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
• On the Structure of Vacancy Ordered Superconducting Alkali Metal Iron Selenide
• Theory of the Magnetic Moment in Iron Pnictides
• 19-F NMR Investigation of Iron-pnictide Superconductor LaFeAsO(0.89)F(0.11)
• Coexistence of superconductivity and antiferromagnetism in single crystals $A_{0.8}F{e}_{2-y}S{e}_2$ (A= K, Rb, Cs, Tl/K and Tl/Rb): evidence from magnetization and resistivity
• Universal linear-temperature dependence of static magnetic susceptibility in iron-pnictides
• 57-Fe Mossbauer study of magnetic ordering in superconducting K_0.85Fe_1.83Se_2.09 single crystals
• 77Se NMR Investigation of the K(x)Fe(2-y)Se(2) High Tc Superconductor (Tc=33K)
• ${}^{75}$As NQR and NMR studies of superconductivity and electron correlations in iron arsenide Li${}_x$FeAs
• 77Se NMR study of pairing symmetry and spin dynamics in KyFe2-xSe2
• Superconductivity mediated by the antiferromagnetic spin-wave in chalcogenide iron-base superconductors
• Superconductivity and normal state properties of single-crystalline Tl0.47Rb0.34Fe1.63Se2 as seen via 77Se and 87Rb NMR

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• Superconductivity in the iron selenide KxFe2Se2 (0 <= x <= 1)
• New ternary ThCr2Si2-type iron-selenide superconducting materials: synthesis, properties and simulations
• Spin reorientation in TlFe1.6Se2 with complete vacancy ordering
• Microscopic coexistence of superconductivity and antiferromagnetism in underdoped Ba(Fe1-xRux)2As2
• Simultaneous optimization of spin fluctuations and superconductivity under pressure in an iron-based superconductor
• Superconducting properties and pseudogap from preformed Cooper pairs in the triclinic (CaFe${}_{1-x}$Pt${}_x$As)${}_{10}$Pt${}_3$As${}_8$
• Breakdown of single spin-fluid model in heavily hole-doped superconductor CsFe2As2
• Review of nuclear magnetic resonance studies on iron-based superconductors
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• Phase Separation, Competition, and Volume Fraction Control in NaFe${}_{1-x}$Co${}_x$As
• Magnetic and structural properties of the iron silicide superconductor LaFeSiH
• Spin fluctuations and pairing symmetry in A${}_x$Fe${}_{2-y}$Se${}_2$: dual effect of the itinerant and the localized nature of electrons