4) Magnon Thermal Conductivity in Low-Dimensional Quantum-Spin Systems

The thermal conductivity κ has been investigated in several copper oxides regarded as low-dimensional quantum-spin systems, using single crystals of good quality grown by the TSFZ method. The κ shows exotic temperature and magnetic-field dependences closely related to the spin state, such as the antiferromagnetic ordered state and the spin-gap state. We have found that magnons have large contribution to κ in some copper oxides, owing to the large exchange interaction between Cu2+ spins.

Graduate School of Engineering, Tohoku University : Kazutaka Kudo,Takashi Noji, Yoji Koike IMR, Tohoku University : Terukazu Nishizaki, Norio Kobayashi Reference : (1) K. Kudo, T. Noji, Y. Koike, T. Nishizaki, N. Kobayashi, "Thermal Conductivity of the Four-Leg Spin-Ladder System La2Cu2O5 Single Crystal", J. Low Temp. Phys., in press. (2) K. Kudo, T. Noji, Y. Koike, T. Nishizaki, N. Kobayashi, "Anisotropic Magnetic Properties and Anomalous Thermal Conductivity in the bc Plane of the Quasi-Two-Dimensional Spin System Cu3B2O6", submitted to J. Phys. Soc. Jpn.