Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 13: Topical Session: Quasicrystals & Complex Metallic Alloys III
MM 13.9: Vortrag
Montag, 11. März 2013, 17:45–18:00, H25
On the evolution of structure and electronic transport properties in Al-Mn — •Syed Sajid Ali Gillani and Peter Häussler — Chemnitz University of Technology, Institute of Physics, 09107 Chemnitz, Germany
A systematic study of thin films of Al-Mn, evaporated at T=4 K, shows mixtures of amorphous, quasi-crystalline, as well as nano-crystalline phases. Their structures have been investigated by electron diffraction, their transport properties and thermal stability by resistivity measurements, indicating clear evidences of resonance effects between global subsystems as there are the Fermi gas as one, and the forming static structure as the other one. The global resonances are self-organizing via their exchange of characteristic momenta and angular momenta, respectively and dominate all the properties including phase stability and phase separation. The amorphous phase shows in r-space spherical periodic order, predominately based on an exchange of characteristic momenta alone. Al-rich alloys show, in addition, features of quasi-crystalline order and Mn-rich alloys an enhanced content of nano-crystalline periodic order. The characteristic distances between theses phases are related among each other and to half the Fermi wavelength λF, indicating resonance effects in all of them. In k-space the corresponding structure factor S(K) shows a resonance peak at scattering vector Kpe = 2kF with an additional prepeak in the range of the quasi-crystalline phase and further peaks in the range of enhanced nano-crystallinity.