Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 27: Quasikristalle

M 27.4: Vortrag

Montag, 7. März 2005, 11:15–11:30, TU H111

Electronic transport and structural properties of amorphous and quasicrystalline Al-TM thin films — •Jose Barzola-Quiquia and Peter Häussler — Institut für Physik, Technische Universität Chemnitz, D-09107, Germany

In the present contribution we present a detailed study and comparison of electronic transport properties and the atomic structure of the amorphous and the quasicrystalline state of Al(CuFe, PdMn, PdFe). The samples are prepared in situ at low temperature (T≈10K) as amorphous thin films. After preparation the samples were annealed at different temperatures and both, transport and structural properties were measured up to the transition to the quasicrystalline state at T>700K. The electronic transport properties show pronounced non- metallic behaviour versus temperature. The atomic structure is characterized by the typical spherical-periodic order of disordered systems. But, additional, local icosahedral order is observed, which gets more pronounced by annealing. This behaviours can be explained in the frame of an electronic stabilization of amorphous systems, very similar to Hume-Rothery alloys. Contrary to Hume-Rothery alloys, in the systems under consideration hybridisation effects between Al-_p with TM-_d electrons play an important rule. Our view on the electronic stabilization gets supported by electronic transport measurements.