Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 13: Electronic Structure of Surfaces II
O 13.12: Vortrag
Montag, 16. März 2015, 18:00–18:15, MA 041
Initial stages of the Fe2ZrSi Heusler alloy formation — •Katerina Horakova1, Jan Honolka1, Jan Lancok1, Vladimir Chab1, and Petr Sajdl2 — 1Institute of Physics, Academy of Sciences of the Czech Republic, 182 21 Prague 8, Czech Republic — 2Institute of Chemical Technology Prague, 166 28 Prague 6, Czech Republic
We measured the electronic structure of clean Zr (0001) surfaces before and after adsorption of submonolayer coverages of Si and Fe atoms. Measurements were done using k-space microscopy. Our aim is to study the initial stages of the formation of Fe2ZrSi Heusler alloys on this surface. Our work is motivated by a passivation process of zirconium, widely used in the nuclear power industry. Fe and Si are deposited sequentially on the clean Zr surface. The structure of the surface was analysed by LEED and XPS. Different chemical states of Zr were found as a function of temperature and the composition. On a clean surface we detected two different chemical states of the Zr, one corresponding to the metal Zr, and the second to the bond with hydrogen naturally trapped in the bulk. After Si deposition, a slight annealing at 400°C of the Si layer produces a new quasicrystalline structure connected with strong changes of the electronic structure at Ef. These changes are probably a result of Zr-Si-H bonding. The deposition of Fe and subsequent annealing produces a disordered layer only.