Original scientific paper

Thermal conductivity of Al-Cr-Fe approximant compounds

Željko Bihar ; Institute of Physics, Bijenička 46, POB 304, HR-10 001 Zagreb, Croatia
Ante Bilušić ; Institute of Physics, Bijenička 46, POB 304, HR-10 001 Zagreb, Croatia
Ana Smontara ; Institute of Physics, Bijenička 46, POB 304, HR-10 001 Zagreb, Croatia
Janez Dolinšek ; J. Stefan Institute, University of Ljubljana, Jamova 39, SI-1000 Ljubljana, Slovenia

Abstract

We have investigated electrical resitivity and thermal conductivity of quasicrystalline compounds of the Al-Cr-Fe system: a gamma-brass phase (γ-AlCrFe) and a mixture of two orthorhombic approximants of the decagonal phase (O1/O2-AlCrFe) with properties which are in many respects intermediate to regular metals and quasicrystals. The electrical resistivities show very weak temperature dependence and the resistivity values are in between regular metals and aluminum-based quasicrystals. Thermal conductivity data show that the electronic and lattice contributions are of comparable size. While the electronic contribution can be described by the Wiedemann–Franz law, the lattice contribution can be reproduced by a sum of a long-wavelength phonons and hopping terms. At the lowest measured temperature, scattering of phonons on stacking-fault-like defects limits the heat transport. This type of defects has also been observed in the structural investigations. The results indicate that transport properties of quasicrystalline approximants are not determined by the short-range atomic order only, but are affected by both, the short-range quasiperiodic and long-range periodic atomic orders.

Keywords

Al-Cr-Fe system; quasicrystalline approximants; thermal conductivity

Hrčak ID:

302058

URI

https://hrcak.srce.hr/302058

Publication date:

1.3.2006.

Article data in other languages: croatian

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