| Popis: |
We performed investigations of the electrical resistivity, thermopower and thermal conductivity of a single-crystalline i-Al64Cu23Fe13 as well as a polycrystalline i-Al63Cu25Fe12 icosahedral quasicrystal, for comparison. Electrical resistivity of both samples, the monocrystalline i-Al64Cu23Fe13 and the polycrystalline i-Al63Cu25Fe12, exhibits a negative temperature coefficient with ro(4K)=3950Ohmcm and ro(4K)=4900Ohmcm, and the ratio ro(4K)/ro(300K)=1.8, ro(4K)/ro(300K)=1.7, respectively. The thermopowers are large with negative sign, in addition, the thermopower of single-crystalline i-Al64Cu23Fe13 exhibits a sign reversal at T=278 K. The thermal conductivity is anomalously low, order of 1 W/mK at room temperature, with a slightly different temperature variation at low temperatures. On the basis of these results, we concluded that there are no systematic differences between the high-quality monocrystalline and polygrain icosahedral i-Al-Cu-Fe quasicrystals. Moreover, the reported transport properties of i-Al-Cu-Fe appear to be intrinsic to this family of icosahedral quasicrystals. |
