Improvement of thermoelectric properties of icosahedral AlPdRe quasicrystals by Fe substitution for Re

Abstract

The thermoelectric properties of quaternary icosahedral AlPdReFe quasicrystals obtained by replacing Re with Fe in icosahedral AlPdRe quasicrystals have been studied according to the guiding principle of weakly bonded rigid heavy clusters (WBRHCs). Anisotropy in the microstructures of arc-melted and annealed samples was found, and the electrical and thermal conductivities are larger in the direction perpendicular to the bottom of the arc-melted button than in the parallel case. The dimensionless figure of merit (ZT) in the perpendicular direction was increased 2.6 times from 0.08 to 0.21 by Fe substitution for Re in the icosahedral AlPdRe quasicrystals, which was caused by the increase of the Seebeck coefficient and the decrease of the phonon thermal conductivity, and the increase of the electrical conductivity, expected and not for the WBRHCs, respectively. © 2007 American Institute of Physics.