NMR Study of Over-doped NaFe<sub>1-x</sub>Cu<sub>x</sub>As Single Crystals

ORAL

Abstract

We present our NMR study of over-doped pnictide NaFe1-xCuxAs, which has been demonstrated to be a possible Mott insulator near x ≈ 0.5 [1,2]. Our NMR spectra show two inequivalent 23Na sites due to Cu dopants. Both 23Na and 75As NMR spectra show a possible formation of stripe-like ordering of Fe and Cu in the 35% and 50% Cu-doped samples. The large Curie-Weiss-like magnetization due to impurity effects results in strongly inhomogeneous field distribution through out the heavily Cu-doped samples, significantly broadening both 23Na and 75As spectra. Our 23Na spin-lattice relaxation data shows an enhanced relaxation rate in regions close to Cu dopants.

*This work is supported by the DOE BES under grant DE-FG02-05ER46248, DE-FG02-05ER46202, and the NHMFL by NSF and the State of Florida.

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Presenters

  • Yizhou Xin

    • Northwestern University
    • Northwestern Univ

Authors

  • Yizhou Xin

    • Northwestern University
    • Northwestern Univ

  • Jeongseop Lee

    • Northwestern Univ

  • Ingrid Stolt

    • Northwestern Univ

  • William Halperin

    • Northwestern Univ
    • Physics and Astronomy, Northwestern Univ
    • Physics, Northwestern University

  • Yu Song

    • University of California Berkeley
    • Univ of California - Berkeley

  • Weiyi Wang

    • Rice Univeristy
    • Rice University

  • Pengcheng Dai

    • Physics and Astronomy, Rice University
    • Rice University
    • Physics, Rice University
    • Rice Univeristy

  • Chongde Cao

    • Northwestern Polytechnical Univeristy

  • Arneil Reyes

    • National High Magnetic Field Laboratory, Florida State University
    • NHMFL, Florida State University
    • National High Magnetic Field Laboratory