No abstract

Thermoelectric properties of a cubic quasicrystalline approximant in Al-Cu-Ir system were investigated experimentally and theoretically. A homogeneous sample with no secondary phase was synthesized using an arcmelting and a sparkplasmasintering processes followed by heat treatment at 1173 K, and its thermoelectric properties were measured at temperatures between 373 K and 1023 K. Theoretical calculations of the thermoelectric properties were performed under three different approximations, i.e., constantrelaxationtime, constantmeanfreepath, and constantdiffusioncoeffi cient approximations, for the energy dependence of the relaxation time of the electrons. The experimental Seebeck coeffi cient was well reproduced, and physically acceptable lattice thermal conductivity was estimated only under constantdiffusioncoeffi cient approximation for the present material. Thermoelectric fi gure of merit zT of the present sample was lower than 01, and the maximum value of zT ≈ 03 achievable by electron doping was predicted by the theoretical calculation under the rigidband approximation.