Tuning the ground state of the Kondo lattice in U$T$Bi$_{2}$ ($T = Ag, Au$) single crystals

ORAL

Abstract

Motivated by the interesting magnetic anisotropy found in the Ce-based heavy fermion family Ce$TX_2$ ($T$ = transition metal, $X = $ pnictogen), here we study the novel U-based parent compounds U$T$Bi$_{2}$ ($T =$ Ag, Au) by combining magnetization, electrical resistivity, and heat-capacity measurements. The single crystals, synthesized by the self-flux method, also crystallize in the tetragonal HfCuSi$_{2}$-type structure (space group P4/nmm). Interestingly, although UAgBi$_{2}$ is a low-$\gamma$ antiferromagnet below $T_{N} = 181$ K, UAuBi$_{2}$ is a moderately heavy uniaxial ferromagnet below $T_{c} = 22$ K. Nevertheless, both compounds display the easy-magnetization direction along the $c$-axis and a large magnetocrystalline anisotropy. Our results point out to an incoherent Kondo behaviour in the paramagnetic state and an intricate competition between crystal field effects and two anisotropic exchange interactions, which lead to the remarkable difference in the observed ground states.

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Authors

  • Priscila Rosa

    University of California, Irvine

  • Yongkang Luo

    Los Alamos Natl Lab, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

  • Pascoal Pagliuso

    University of Campinas

  • Eric Bauer

    Los Alamos National Laboratory, LANL, Los Alamos Natl Lab, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA, National High Magnetic Field Laboratory

  • Joe Thompson

    LANL, Los Alamos Natl Lab, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

  • Zachary Fisk

    University of California at Irvine, Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA, University of California, Irvine