Evidence for the Ballistic Thermal Conduction in the One-Dimensional Spin
System Sr2 CuO3
Nobuo Takahashia , Takayuki Kawamataa,b , Tadashi Adachia,b , Takashi Nojia,b , Yoji Koikea,b , Kazutaka
Kudoc , and Norio Kobayashic
a
Department of Applied Physics, Tohoku University, 6-6-05, Aoba, Aramaki, Sendai 980-8579, Japan
JST, CREST
c
Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
b
The compound Sr2 CuO3 has one-dimensional (1D) Cu2+ -spin chains regarded as ideal 1D antiferromagnetic Heisenberg chains, where the ballistic thermal conduction due to magnons is theoretically
expected to be realized. 1, 2 Actually, large thermal conductivity due to magnons, κmag , was observed in
Sr2 CuO3 by Sologubenko et al. 3 We have measured the thermal conductivity along the chain, κchain , of
Sr2 Cu1−x Pdx O3 single crystals with nonmagnetic impurities of Pd2+ in order to investigate the possible
ballistic thermal conduction. It has been found that the mean free path of magnons estimated from
κmag , which is obtained by subtracting the thermal conductivity due to phonons from κchain using the
Debye model, is comparable with the average interval between spin defects estimated from the magnetic
susceptibility measurements. This proves that the thermal conduction due to magnons is ballistic.
1
S. Fujimoto et al., J. Phys. A 31, 465 (1998).
X. Zotos et al., Phys. Rev. Lett. 82, 1764 (1999).
3
A. V. Sologubenko et al., Phys. Rev. B 64, 054412 (2001).
2
Sorting category: Cb Magnetism and properties of solids
Keywords: one-dimensional spin system, Sr2 CuO3 , thermal conductivity, impurity effects
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