Low-temperature transport properties of the epsilon-phases Al-Pd-(Mn, Fe, Co, Rh)
Nizkotemperaturne transportne lastnosti epsilon-faz Al-Pd-(Mn, Fe, Co, Rh, ...)

english

2008

volume 42, issue 3

aluminium alloy 

Inštitut za kovinske materiale in tehnologije
(Obvezni izvod spletne publikacije)

We report results on low-temperature investigations of the electrical and thermal conductivity of the epsilon-phases in the Al-Pd-Fe, Al-Pd-Co and Al-Pd-Rh systems, which are characterized by giant unit cells with a quasicrystals-like cluster substructure. The electrical resistivity is of the order of 100 muOmega cm and shows a weak temperature dependence in the investigated temperature interval 4-300 K. An interesting feature of the epsilon-phases is their low thermal conductivity, which at room temperature is comparable to that of thermally insulating amorphous SiO2 and Zr/YO2 ceramics. While SiO2 and Zr/YO2 are also electrical insulators, epsilon-phases exhibit an electrical conductivity typical of metallic alloys and offer an interesting combination of an electrical conductor and a thermal insulator. The reason for the weak thermal conductivity of the epsilon-phases appears to be structural: large and heavy atomic clusters of icosahedral symmetry in the giant unit cell prevent the propagation of extended phonons and the lattice can no more efficiently participate in the heat transport.

08.06.2010