Magnetic quantum tunneling in Fe-doped Li<sub>3</sub>N: stable but manipulable states.

ORAL

Abstract

Li2(Li1-xFex)N shows extremely large magnetic anisotropy and coercivity that are based on the presence of unquenched orbital moments [1,2]. For low Fe-concentrations the spin-relaxation becomes temperature-independent indicating a crossover from thermal excitations to the quantum tunneling regime at T = 10 K. The resonant character of this tunneling process is proven by a strong increase of the spin-flip probability in transverse magnetic fields. Longitudinal fields, on the other hand, lift the ground state degeneracy and destroy the tunneling condition. An increase of the relaxation time by four orders of magnitude in external fields of only a few millitesla reveals exceptionally sharp tunneling resonances. Accordingly the system can be set from stable to manipulable by tuning from off- to on-resonant using small applied fields. Li2(Li1-xFex)N represents a comparatively simple and clean model system that opens the possibility to study and utilize magnetic quantum tunneling at liquid helium temperatures.
[1] Nat. Commun. 5:3333 (2014)
[2] Nanoscale 9, 10596 (2017)

*This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - JE 748/1 and the U.S. Department of Energy, Office of Basic Energy Science under contract number DE-AC02-07CH11358.

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Presenters

  • Anton Jesche

    • EP VI, University of Augsburg

Authors

  • Manuel Fix

    • EP VI, University of Augsburg

  • James Atkinson

    • Physics, University of Central Florida

  • Paul Canfield

    • Ames Laboratory and Iowa State University
    • Ames Laboratory, Iowa State University
    • Department of Physics and Astronomy, Iowa State University
    • Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University
    • Iowa state university/Ames Laboratory
    • Ames Laboratory and Iowa State Univ
    • Iowa State University and Ames Laboratory
    • Iowa State University/Ames Laboratory
    • Iowa State University
    • Iowa State University / Ames Laboratory
    • Dept. of Physics, Iowa State Univ
    • Ames Lab
    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University
    • Iowa State Univ
    • Ames Laboratory
    • Department of Physics and Astronomy, Ames Laboratory and Iowa State University

  • Enrique Del Barco

    • Univ of Central Florida
    • Physics Department, University of Central Florida
    • Physics, University of Central Florida

  • Anton Jesche

    • EP VI, University of Augsburg