Thermal Conductivity in the Triangular-Lattice Antiferromagnet Ba3CoSb2O9

27th International Conference on Low Temperature Physics

Naruse, K.^1 ; Kawamata, T.^1 ; Ohno, M.^1 ; Matsuoka, Y.^1 ; Sudo, H.^1 ; Nagasawa, H.^1 ; Hagiya, Y.^1 ; Sasaki, T.^2 ; Koike, Y.^1

Department of Applied Physics, Tohoku University, Sendai

980-8579, Japan^1

Institute for Materials Research, Tohoku University, Sendai

980-8577, Japan^2

关键词: Antiferromagnetic transition temperature;    Magnetic field dependences;    Magnetic fluctuation;    Magnetic frustrations;    Magnetic state;    Magnon scattering;    Mean free path of phonons;    Triangular lattice antiferromagnet;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/4/042014/pdf
DOI  :  10.1088/1742-6596/568/4/042014

来源: IOP

【 摘 要 】

We have measured the thermal conductivity in the ab-plane, κab, and along the c-axis, κc, of single crystals of the S 1/2 triangular-lattice antiferromagnet Ba3CoSb2O9in zero field and magnetic fields. In zero field, it has been found that both κaband κcshow a similar broad peak around 40 K, suggesting that the thermal conductivity due to phonons is dominant in this compound and that the mean free path of phonons is suppressed so much by strong magnetic-fluctuations due to the magnetic frustration. It has also been found that both κaband κcshow a kink at the antiferromagnetic transition temperature TN. In magnetic fields parallel to the ab-plane up to 14 T, magnetic-field dependences of both κaband κcat temperatures below and above TNhave been found to be understood taking into account the phonon-magnon scattering in the so-called 120° structure phase and the up-up-down (UUD) phase, while the minima of κaband κcobserved in the middle of the UUD phase have not been understood. This suggests the occurrence of some change of the magnetic state in the middle of the UUD phase.