Thermoelectric performance of Al-Pd-Mn quasicrystals: Comparison with (1/1,2/1-)AlPdMnSi approximants and improvement by Ga substitution for Al

Abstract

We report the thermoelectric properties of polygrain icosahedral Al-Pd-Mn quasicrystal and compare with those of (1/1, 2/1-)AlPdMnSi approximant crystals. To improve the dimensionless figure of merit (ZT), we substitute Ga for Al atoms in Al-Pd-Mn quasicrystal in accordance with the guiding principle of "weakly bonded rigid heavy clusters" (WBRHCs). Although the thermoelectric properties do not obey the WBRHCs principle, the maximum ZT increased by a factor of 1.4 from 0.18 for Al71Pd20Mn 9 to 0.26 for Al68Ga3Pd20Mn 9 quasicrystal. © by Oldenbourg Wissenschaftsverlag.