ACTA

Experimental Study of the Thermal Transport in CsNiF₃ - An S = 1 Quantum Chain

V. Tkáč^a, A. Orendáčová^a, M. Orendáč^a, D. Legut^b, K. Tibenská^c, A. Feher^a, M. Poirier^d and M.W. Meisel^e
^aCentre of Low Temperature Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 041 54 Košice, Slovakia
^bInstitute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, CZ-616 62 Brno, Czech Republic
^cFaculty of Aeronautics, Technical University, Rampová 7, 041 21 Košice, Slovakia
^dRegroupement Québécois sur les Matériaux de Pointe, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
^eDepartment of Physics and the National High Magnetic Field Laboratory, University of Florida, Gainesville, Florida 32611-8440, USA

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The heat transport in a single-crystal of CsNiF₃ has been performed in the temperature range from 2 K to 7 K in a zero magnetic field, B = 0, as well as in sufficiently large magnetic fields, B = 6 T and 9 T, inducing the ferromagnetic ground state along the hard c-axis. CsNiF₃ represents an S = 1 quasi-one-dimensional XY ferromagnet with the intra-chain exchange coupling J/k_B ≈ 24 K, single-ion anisotropy D/k_B ≈ 8 K, and ordering temperature T_N = 2.7 K. Comparison of the phonon and magnon velocities suggests that phonons are the main heat carriers in this magnetic insulator. The thermal conductivity in B = 0 was analysed in the frame of a standard Debye model. The temperature dependence of the effective phonon mean free path was calculated from the experimental data, and the enhancement of the phonon mean free path in B ≠ 0 was obtained, indicating that magnons act as scattering centers for phonons.

DOI: 10.12693/APhysPolA.121.1098
PACS numbers: 75.30.Et, 75.40.Cx, 66.70.Lm, 75.30.Ds