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arXiv · 1704.01966

In-situ observation of temperature-dependent segregation of Ni adatoms on oriented Pd surfaces

Samantha Zimnik·Marcel Dickmann·Christoph Hugenschmidt
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Abstract

We report the direct observation of the in-situ temperature-dependent surface segregation of Ni adatoms on single crystalline Pd surfaces using Positron annihilation induced Auger Electron Spectroscopy (PAES). For this study, a single atomic layer of Ni was grown on Pd with the crystallographic orientations Pd(111), Pd(110) and Pd(100). The sample temperature was increased from room temperature to 350$^\circ$C and the intensity of the Ni and Pd signal was evaluated from the recorded PAES spectra. Due to the outstanding surface sensitivity of PAES a clear tendency for Pd segregation was observed for all samples. Moreover the activation temperature T$_0$ for surface segregation was found to depend strongly on the surface orientation: We determined T$_0$ to 172$\pm$4$^\circ$C, 261$\pm$12$^\circ$C and 326$\pm$11$^\circ$C for Pd(111), Pd(100) and Pd(110), respectively.

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Samantha Zimnik, Marcel Dickmann, Christoph Hugenschmidt. 2017-04-06. In-situ observation of temperature-dependent segregation of Ni adatoms on oriented Pd surfaces. https://arxiv.org/abs/1704.01966

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