Thermal conductivity of thermoelectric rhodium oxides measured by a modified Harman method

摘要

We report the thermal conductivity kappa and figure of merit Z of thermoelectric rhodium oxides using a modified Harman method. kappa and Z are obtained to be 30mW/(cm.K) and 1 x 10(-4) K-1 at 200K, respectively, which are comparable to those of thermoelectric-layered cobalt oxides. In particular, Z = 2.3 x 10(-4) K-1 is found in the pseudo-one-dimensional Ba1.2Rh8O16 at 75 K, which is the second-best value among oxides below 300 K. We show that the modified Harman method is a convenient and powerful tool for investigating the thermoelectric properties of small crystals.