FIZIKA A 15 (2006) 1 , 51-60
THERMAL CONDUCTIVITY OF Al-Cr-Fe APPROXIMANT COMPOUNDS
ŽELJKO BIHARa, ANTE BILUŠIĆa, ANA SMONTARAa,1 and
aInstitute of Physics, Bijenička 46, POB 304, HR-10 001 Zagreb, Croatia
bJ. Stefan Institute, University of Ljubljana, Jamova 39, SI-1000 Ljubljana, Slovenia
1E-mail address: firstname.lastname@example.org
Received 11 July 2005; Accepted 14 November 2005
Online 10 November 2006
We have investigated electrical resitivity and thermal conductivity of
quasicrystalline compounds of the Al-Cr-Fe system: a gamma-brass phase
(g-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.
PACS numbers: 61.44.Br, 71.23.Ft
Al-Cr-Fe system, quasicrystalline approximants, thermal conductivity