Original scientific paper

Heat Conduction in Complex Metallic Alloys

Ante Bilušić ; Department of Physics, Faculty of Science, University of Split, Nikole Tesle 12, HR-21000 Split, Croatia; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, P. O. Box 304, HR-10001 Zagreb, Croatia
Igor Smiljanić ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, P. O. Box 304, HR-10001 Zagreb, Croatia
Željko Bihar ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, P. O. Box 304, HR-10001 Zagreb, Croatia
Denis Stanić ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, P. O. Box 304, HR-10001 Zagreb, Croatia
Ana Smontara ; Laboratory for the Physics of Transport Phenomena, Institute of Physics, Bijenička c. 46, P. O. Box 304, HR-10001 Zagreb, Croatia

Abstract

Thermal conductivity, κ, of ε-phase Al₇₃Pd₂₅Fe₂ and "Bergman phase" Mg-Al-Zn is presented, which resembles the features common to all complex metallic alloys: relatively low value, shallow local maximum or change of slope at approximately 50 K, and a rise above 100 K. The electron contribution, κ_el, is calculated using Wiedemann-Franz law, while the calculation of the phonon thermal conductivity, κ_ph, below 50 K is calculated employing Debye model. The sum of the two does not explain the experimental data at higher temperatures (above 100 K). This discrepancy is analyzed in three competitive ways: assuming an increase of an effective Lorenz number, taking into account the hopping of localized lattice vibrations, and employing a "bipolar diffusion effect", known from the theory of semiconductors. While the results of the former two approaches confirm other findings in literature, "bipolar diffusion effect" needs to be adopted for the specific electron structure of complex metallic alloys.

Keywords

thermal conductivity; Wiedemann-Franz law; Debye model; ocalized lattice vibrations; bipolar diffusion

Hrčak ID:

52151

URI

https://hrcak.srce.hr/52151

Publication date:

30.4.2010.

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