Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 28: Amorphous and Liquid Materials III

MM 28.5: Vortrag

Donnerstag, 30. März 2006, 12:45–13:00, IFW B

On the plasma resonance of binary amorphous Al-TM alloys — •Martin Stiehler, Uta Giegengack, Jose Barzola-Quiquia, Jan Rauchhaupt, Steffen Schulze, and Peter Häussler — Chemnitz University of Technology, Institute of Physics, 09107 Chemnitz, Germany

Amorphous phases are ideal systems for investigating the mechanisms of structure formation. During the last years we reported about measurements of structure, electrical resistivity, thermopower, Hall-effect and thermal stability of binary a-AlTM alloys with 3d TM elements. The results were interpreted in a hybridization enhanced Hume-Rothery model with a composition-dependent valency of the TM.

Here we report on a unique systematics in the plasma resonance data of binary a-AlTM alloys. Conveniently, plasma resonance signals are used to determine the electron density of materials. For amorphous semiconductors we could apply this method in excellent agreement to the free electron model by calculating the electron density using the valencies of the elements from the periodic table. In a-AlTM alloys with 3d TM, the situation is different. Here such a simple approach fails. But with the valency of Al from the periodic table, in all this systems the 3d TM, including Ni, Co, Fe, Mn, Cr, V, Ti, and even Ca, seem to exhibit the same valency over the complete concentration range with no respect to the above mentioned hybridization effects. This result may be explained in a refined hybridization model.