Naslov
Phonon scattering in quasicrystalline i-Al72Pd19.5Mn8.5 : A study of the low-temperature thermal conductivity
(Phonon scattering in quasicrystalline i-Al72Pd19.5Mn8.5: A study of the low-temperature thermal conductivity)

Autori
Bilušić, Ante ; Smontara, Ana ; Dolinšek, J. ; McGuiness, P. ; Ott, H.R.

Izvornik
Journal of alloys and compounds (0925-8388) 432 (2007), 1/2; 1-6

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
quasicrystals; heat conduction; scanning and transmission electron

Sažetak
In this work, we have analyzed the thermal conductivity of an icosahedral quasicrys- tal i -Al72Pd19.5Mn8.5 in a temperature range between 0.4 K and 300 K. Tha analysis was made in frames of two models: a Debye model (which implies the quadratic den- sity of vibrational states and the existence of acoustical phonons), and the model of the harmonic approximation with non-quadratic density of vibrational states. The results of the Debye model employed for two temperature regions, T < 40 K and T < 1K, are not compatible to each other. Contrary to T < 1 K-region, fit T < 40 K tunneling states are not present in fit result, although there exist a number of experimental evidences which intrinsically relate the quasicrystal struc- ture and tunneling states. The fit of the experimental data to the harmonic model with non-quadratic vibrational density of states points out the phonon scattering on the tunneling states. In all cases phonon scattering on structural defects of the stacking-fault type resulted from fits. TEM experiment indeed showed the existence of stacking-fault defects, with the number of stacking faults of the same order of magnitude as that calculated by the fitting procedures.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
This work was supported in a part by the 6th Framework EU Network of Excellence 'Complex Metallic Alloys' (Contract No. NMP3-CT-2005-500140)

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