We have measured the temperature dependences of the thermal conductivity of Ba2Cu3−xMxO4Cl2 (M = Pd, Ni, Co; x ¼ 0; 0:03) single crystals including two-dimensional (2D) Cu3O4 planes consisting of a strong 2D spin network of CuA 2+ spins and a weak 2D spin network of CuB 2+ spins. It has been found that the thermal conductivity due to spins, κspin, exists in the thermal conductivity parallel to the Cu3O4 plane owing to the strong 2D spin network of CuA 2+ spins and exhibits a broad peak around room temperature. The maximum value of κspin is ∼7 W=Km and comparable with that in Nd2CuO4 with almost the same 2D spin network of Cu2+ spins as CuA 2+ spins in Ba2Cu3O4Cl2. The κspin has been found to be suppressed by 1% impurities on account of the decrease in the mean free path of magnetic excitations, suggesting that κspin is expected to be enhanced in 2D quantum spin systems such as Ba2Cu3O4Cl2 by reducing the amount of impurities in a single crystal.
ASJC Scopus subject areas
- Physics and Astronomy(all)