engleski

Thermal conductivity of complex metallic alloys

The term “complex metallic compounds” comprises a great number of compounds characterized by their large unit cells that can contain up to a thousand atoms. The paper views the heat and electric transport properties of the class of these compounds known also as quasi-crystalline approximants, with the unit cells formed of polytetrahedral structures also present in quasicrystals. The simultaneous long-range periodicity on the physical-length scale and the presence of non-periodicity of polytetrahedral structures on the short-range length scale causes a crossover of space localization and delocalization of atomic vibrations and current carriers. The electrical conductivity in temperature range 1.5 K- R.T. is weakly temperature dependent, that is explained as an interplay between the delocalization (due to the long-range periodicity) and the localization (due to the short range polytetrahedral order) of charge carriers, while the thermal conductivity vs. temperature behavior is similar to those for thermal insulators, with the remark that half of the net heat transport is governed by the charge carriers.

complex metallic alloys, electrical resitivtiy, thermal conductivity

The paper was presented at European School in Materials Science, Ljubljana, Slovenia, May 21-26 2007 as the Basic tutorials given by Ana Smontara This work was supported by the 6th Framework EU Network of Excellence 'Complex Metallic Alloys' (Contract No. NMP3-CT-2005-500140)