Thermal conductivity of Ca3Co2O6 single crystals

Ca3Co2O6 is a rare example of one-dimensional Ising spin-chain material with the moments preferentially aligned along the c axis. In this work, we study the c-axis thermal conductivity (kappa(c)) of Ca3Co2O6 single crystal at low temperatures down to 0.3 K and in magnetic fields up to 14 T. The zero-field kappa(c)(T) shows a large phonon peak and can be well fitted by using the classical Debye model, which indicates that the heat transport is purely phononic. Moreover, the low-T kappa(c)(H) isotherms with H parallel to c display a field-independent behavior. These results indicate that there is no contribution of magnetic excitations to the thermal conductivity in Ca3Co2O6 , neither carrying heat nor scattering phonons, which can be attributed to the Ising-like spin anisotropy. (C) 2017 Author(s).