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Evolution of magnetic-field-induced magnetic ordering in the layered structure quantum Heisenberg triangular-lattice antiferromagnet Ba<sub>3</sub>CoSb<sub>2</sub>O<sub>9</sub>

ORAL

Abstract

Quantum fluctuations in the effective spin-1/2 layered-structure triangular-lattice quantum Heisenberg antiferromagnet Ba3CoSb2O9 lift the classical degeneracy of the antiferromagnetic ground state in magnetic field, producing a series of novel magnetic-field-induced spin structures. We have used specific heat, neutron diffraction, thermal conductivity, and magnetic torque measurements to map out the phase diagram of this system as a function of magnetic field intensity and orientation relative to the crystallographic ab plane. We report previously unobserved magnetic-field-induced phase transitions and a field-orientation dependence that deviates from theoretical predictions near H ‖ c . A tetracritical point in the high field phase diagram and the second-order nature of the transitions eliminates several of the theoretically proposed spin structures for the high field phases and provides new guidance into the nature of the magnetic order in each phase.

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Presenters

  • Nathanael Fortune

    Department of Physics, Smith College

Authors

  • Nathanael Fortune

    Department of Physics, Smith College

  • Qing Huang

    Department of Physics and Astronomy, University of Tennessee, Knoxville, University of Tenessee, Department of Physics and Astronomy, University of Tennessee, National Institute of Standards and Technology, University of Tennessee

  • Tao Hong

    Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge National Laboratory, Oak Ridge National Lab

  • Yasumasa Takano

    Department of Physics, University of Florida, University of Florida, Physics, University of Florida

  • Scott Hannahs

    National High Magnetic Field Laboratory, Florida State University

  • Eun Sang Choi

    National High Magnetic Field Laboratory, Florida State University, National High Magnetic Field Laboratory, National High Magnetic Field Laboratory and Department of Physics, Florida State University, National High Magnetic Field Lab, Physics, Florida State University, National High Field Magnet Laboratory, Florida Sate University

  • Jie Ma

    School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai Jiao Tong University

  • Zhiying Zhao

    State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter

  • N. Li

    Department of Physics, Hefei National Laboratory for Physical Sciences at Microscale

  • Haidong Zhou

    Dep. Physics and Astronomy, University of Tennessee, Knoxville TN, Department of Physics and Astronomy, University of Tennessee, Knoxville, University of Tenessee, University of Tennessee, Knoxville, Physics and Astronomy, University of Tennessee at Knoxville, University of Tennessee, Department of Physics and Astronomy, University of Tennessee