Coexistence of antiferromagnetic and ferromagnetic spin correlations in Ca(Fe$_{1-x}$Co$_{x})_{2}$As$_{2}$ studied by$^{\, 75}$As NMR

ORAL

Abstract

Recent nuclear magnetic resonance (NMR) measurements revealed the coexistence of stripe-type antiferromagnetic (AFM) and ferromagnetic (FM) spin correlations in both the hole- and electron-doped BaFe$_{2}$As$_{2}$ families of iron-pnictide superconductors by a Korringa ratio analysis.[1] Motivated by the NMR work, we have carried out $^{75}$As NMR measurements in another iron pnictide superconducting family, Ca(Fe$_{1-x}$Co$_{x})_{2}$As$_{2\, }$[2] in order to investigate magnetic fluctuations, especially focusing on possible existence of FM fluctuations. By analyzing $^{75}$As NMR data, we found clear evidence for the coexistence of stripe-type AFM and FM spin correlations in the Ca(Fe$_{1-x}$Co$_{x})_{2}$As$_{2\, }$system. In this talk, we discuss the characteristic magnetic fluctuations in the system. [1] P. Wiecki, et al., Phys. Rev. Lett. \textbf{115}, 137001 (2015). [2] J. Cui, et al., Phys. Rev. B \textbf{92}, 184504 (2015); J. Cui, et al., Phys. Rev. B (in print).

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Authors

  • Yuji Furukawa

    Ames Laboratory and Dept. of Phys. and Astro., Iowa State University

  • Jinfang Cui

    Ames Laboratory and Chem. Dept., Iowa State University

  • Paul Wiecki

    Ames Laboratory and Dept. of Phys. and Astro., Iowa State University

  • Sheng Ran

    Ames Laboratory and Dept. of Phys. and Astro., Iowa State University

  • Serguei Budko

    Iowa State Univ Ames Laboratory, Iowa State Univ, $^A$Ames Laboratory US DOE, $^B$Department of Physics and Astronomy, $^C$Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA., Ames Laboratory US DOE, and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA, Ames Laboratory, Dept. of Physics, ISU, Dept. of Physics, Washington University, St. Louis, ICQM, School of Physics, Peking University, Ames Laboratory and Dept. of Phys. and Astro., Iowa State University, Iowa State Univ and Ames Laboratory

  • Paul Canfield

    Iowa State Univ Ames Laboratory, Ames Laboratory/ Iowa State University, Ames, IA 50011, USA, Iowa State Univ, $^A$Ames Laboratory US DOE, $^B$Department of Physics and Astronomy, $^C$Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA., Iowa State University/ Ames LabLaboratory, Ames Lab, Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Laboratory and Dept. of Phys. and Astro., Iowa State University, Ames Laboratory and Department of Physics, Iowa State University, Ames, Iowa, Iowa State Univ and Ames Laboratory, Ames Lab and Department of Physics, Iowa State University, Ames, Iowa