Calorimetric determination of magnetic phase diagram of Ba$_{3}$CoSb$_{2}$O$_{9}$

ORAL

Abstract

We report heat capacity measurements as a function of temperature, magnetic field, and field angle for the spin 1/2 triangular antiferromagnet Ba$_{3}$CoSb$_{2}$O$_{9}$, for fields up to the saturation field of 32.5 T and temperatures down to 0.1 K. The system behaves as a frustrated Heisenberg antiferromagnet with weak xy anisotropy. For magnetic fields applied along the a axis, 3 main magnetic phases are expected [1], each corresponding to a different spin arrangement: a low field ``Y'' phase, an intermediate ``up - up - down'' phase, and a high field 'V' phase. We find instead 5 distinct magnetic phase transitions with increasing field, suggesting that the ``Y' and ``V'' phases split into alternating and non-alternating co-planar subphases. \\[4pt] [1] A.V. Chubukov \& D.I. Golosov, J.Phys.Cond.Mat 3, 69 (1991).

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Authors

  • Nathanael Fortune

    Department of Physics, Smith College, Northampton, MA, Department of Physics, Smith College

  • Scott Hannahs

    National High Magnetic Field Lab, Tallahassee, FL, National High Magnetic Field Laboratory

  • Ju-Hyun Park

    National High Magnetic Field Laboratory

  • H.D. Zhou

    University of Tennessee and National High Magnetic Field Laboratory, Florida State University, University of Tennessee - Knoxville, Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, Department of Physics and Astronomy, University of Tennessee, University of Tennessee, Department of Physics and Astronomy, University of Tennessee - Knoxville, University of Tennessee, TN, USA

  • Christopher Aoyama

    Department of Physics, University of Florida

  • Yasumasa Takano

    Department of Physics, University of Florida, Gainesville, FL, Department of Physics, University of Florida