Possible coexistence of antiferromagnetic and ferromagnetic spin fluctuations in UTe<sub>2</sub> revealed by <sup>125</sup>Te NMR under pressure

ORAL

Abstract

UTe2 is a newly discovered heavy-fermion superconductor proposed to be an end member of the U-based ferromagnetic (FM) superconductors. The spin-triplet superconducting state in UTe2 mediated by FM spin fluctuations has been proposed by muon spin relaxation and nuclear magnetic resonance measurements (NMR). Recently, neutron scattering measurements detected the presence of antiferromagnetic (AFM) spin fluctuations in UTe2. In this study, we carried out 125Te NMR measurements on a single crystal UTe2 to investigate the evolution of magnetic fluctuations in UTe2 under pressure. From the temperature dependence of 125Te spin-lattice relaxation rates, we propose the possible coexistence of AFM and FM spin fluctuations in the system. In addition, owing to the two different Te sites in the compound, the FM spin fluctuations are considered to exist within the ladders, while the AFM spin fluctuations originate from the inter-ladder magnetic coupling. We point out that although the AFM spin fluctuations exist in the system, the FM spin fluctuations in the ladders may play a more important role in the appearance of the spin-triplet superconducting state of UTe2.

*The research was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the U.S. DOE by Iowa State University under Contract No. DE-AC02- 07CH11358. The National High Magnetic Field Laboratory is supported by the National Science Foundation through NSF/DMR-1644779 and the State of Florida.

–

Publication: Possible coexistence of antiferromagnetic and ferromagnetic spin fluctuations in the spin-triplet superconductor UTe2 revealed by 125Te NMR under pressure "D. V. Ambika, Q.-P. Ding, K. Rana, C. E. Frank, E. L. Green, S. Ran, N. P. Butch, and Y. Furukawa, Phys. Rev. B 105, L220403 (2022). DOI: https://doi.org/10.1103/PhysRevB.105.L220403 "

Presenters

  • Devi Vijayan Ambika

    • Ames Laboratory

Authors

  • Devi Vijayan Ambika

    • Ames Laboratory

  • Qing-Ping Ding

    • Iowa State University and Ames National Laboratory
    • Ames Laboratory

  • Khusboo Rana

    • Ames Laboratory

  • Corey E Frank

    • National Institute of Standards and Tech

  • Elizabeth L Green

    • Florida State University

  • Sheng Ran

    • Department of Physics, Washington University, St.Louis, Missouri
    • Washington University in St. Louis

  • Nicholas P Butch

    • National Institute of Standards and Tech
    • NIST and U. of Maryland

  • YUJI FURUKAWA

    • Iowa State University/Ames National Laboratory
    • Iowa State University and Ames National Laboratory