Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session

MM 20.55: Poster

Dienstag, 27. März 2007, 14:45–18:00, Poster C

Towards a combination of an electrical conductor with a thermal insulator — Ana Smontara¹, Igor Smiljanić¹, •Ante Bilušić^1,2, Benjamin Grushko³, Sergiy Balanetskyy³, Zvonko Jagličić⁴, Stanislav Vrtnik⁵, and Janez Dolinšek⁵ — ¹Institute of Physics, Zagreb, Croatia — ²Faculty of Science, Univ. of Split, Croatia — ³Forschungszentrum Jülich, Germany — ⁴Institute J. Stefan, Ljubljana, Slovenia — ⁵Institute of Mathematics, Physics and Mechanics, Ljubljana, Slovenia

є-phases in the Al-Pd-(Mn,Fe,Co,Rh, …) alloys are complex intermetallics characterized by giant unit cells with quasicrystals-like cluster substructure. To see how the coexistence of two competing physical length scales affect their physical properties, we studied the magnetic, electrical, thermal transport and thermoelectric properties of the є-Al-Pd-Fe, є-Al-Pd-Co and є-Al-Pd-Rh. Magnetic measurements reveal that the materials are diamagnetic, containing tiny fractions of magnetic transition-metal atoms (10-100 ppm). Electrical resistivity shows weak temperature dependence for T = 4 − 300 K. The thermal conductivity is low, comparable to that of thermal insulators amorphous SiO₂ and Zr/YO₂ ceramics at room temperature. While SiO₂ and Zr/YO₂ are also electrical insulators, є-phases exhibit electrical conductivity typical of metallic alloys, so we deal with a combination of an electrical conductor with a thermal insulator. The thermoelectric power of the investigated є-phase families is small, so that these materials do not appear promising candidates for the thermoelectric application. This work was done within the FP6 EU NoE "Complex Metallic Alloys".