We report the electrical and thermal transport properties, including electric resistivity (ρ), Seebeck coefficient (S) and thermal conductivity (κ) of icosahedral Al70Pd22.5Re7.5 quasicrystals in the temperature range between 10 and 300 K. Four Al70Pd22.5Re7.5 samples with a resistivity ratio ℛ = ρ4.2 κ/ρ300 κ ranging from 10.2 to 84.4 were studied. The temperature-dependent resistivities increase with decreasing temperature for all samples, exhibiting a semiconductor-like behaviour. The Seebeck coefficients are positive for the large-ℛ samples (ℛ = 26.3 and 84.4) in the entire temperature range, while S-values become negative for the small-ℛ samples (ℛ = 10.2 and 19.4) below about 120 K. The significant dependence on ℛ of the Seebeck coefficient can be qualitatively understood in the pseudogap scenario. The temperature variation of the thermal conductivity for these materials is quite similar, with values less than 2.5 W m-1 K-1 in the temperature range we investigated. The dimensionless thermoelectric figure of merit (ZT) of this system is estimated to be two orders of magnitude smaller than that of conventional thermoelectric materials.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics