Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 51: Liquid and Amorphous Metals III - Electronic properties of amorphous alloys

MM 51.2: Vortrag

Donnerstag, 3. April 2014, 10:30–10:45, IFW A

What do electron energy loss spectra of binary amorphous Al-TM alloys tell us? — •Martin Stiehler, Syed Sajid Ali Gillani, Pierre Pudwell, Hans Weber, and Peter Häussler — Technische Universität Chemnitz, D-09107 Chemnitz

Some time ago (J. Phys. Chem. Sol. 68 (2007) 1244) we reported on an intriguing systematic feature in the electron energy loss spectra of binary amorphous (a) Al alloys with transition metals (TM) from the fourth period of the periodic table (3d-TM). If interpreted as caused by the excitation of volume plasmons the 3d-TM would have to be counted with a constant valency of 5 e/a irrespective of the particular 3d-TM and irrespective of their concentration in the alloy. In contrary to amorphous alloys without d-states at the Fermi edge this valency would not coincide with the “usual” valency used in calculating, for example, the Fermi-sphere diameter.

In our talk data on a-Al-(Ca,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Y,Pd,Ce) is presented, showing that the aforementioned systematics can also be observed in systems with 4d- and 5d-TM. One possible explanation is based on the influence of inter-/intraband transitions due to the d-states of the TM. For further insight we compare our results with literature data on systems with non-transition metals like Al-(Mg,Zn) in the crystalline state and with amorphous Ga-Mn alloys. The latter is to clarify the role of Al in the systems.