Quantum Critical Behavior in the Disordered Itinerant Ferromagnet UCo<sub>1-<i>x</i></sub>Fe<i><sub>x</sub></i>Ge

ORAL

Abstract


We have investigated low-temperature specific heat of UCo1-xFexGe with x spanning a narrow region around concentration x = 0.22 and x = 0.23 of the purported ferromagnetic quantum phase transition (QPT), at temperatures from 60 mK to 2 K and in magnetic field up to 9 T. The shallow rise of the Sommerfeld coefficient γ = C/T with decreasing temperature for x = 0.22 and x = 0.23 samples is consistent with previously reported higher temperature specific heat data, which was interpreted as evidence of a ferromagnetic QPT. Here, we also find a divergence of specific heat and exponential dependence on temperature, which is consistent with prediction of Belitz-Kirkpatrick-Vojta theory of a ferromagnetic QPT Furthermore, All investigated samples show a rise in specific heat at low-temperature when the external field is applied, interpreted as being due to the Co nuclear Schottky anomaly. Upon subtraction of the Schottky anomaly, the specific heat data indicates that the magnetic field suppresses quantum fluctuations.

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Work at Los Alamos was performed under the auspices of the US Department of Energy, Office of Science, Division of Materials Science and Engineering.

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Presenters

  • Sangyun Lee

    • Los Alamos National Laboratory

Authors

  • Sangyun Lee

    • Los Alamos National Laboratory

  • Eric D Bauer

    • Los Alamos National Laboratory
    • Los Alamos National Lab
    • Los Alamos National laboratory
    • Los Alamos Natl Lab
    • Condensed Matter and Magnet Science Group, Los Alamos National Laboratory
    • Los Alamos National LAborator

  • Filip Ronning

    • Los Alamos National Lab
    • Los Alamos National Laboratory
    • Los Alamos National laboratory
    • Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • Joe Thompson

    • Los Alamos National Lab
    • Los Alamos National laboratory
    • Los Alamos National Laboratory

  • Priscila Rosa

    • Los Alamos National Lab
    • Los Alamos National Laboratory
    • Quantum Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

  • Roman Movshovich

    • Los Alamos National Laboratory
    • MPA-CMMS, Los Alamos National Laboratory