Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 50: Topical Session Modern Atom Probe Tomography IV - Thin Films and Structural Materials

MM 50.1: Vortrag

Donnerstag, 29. März 2012, 11:45–12:00, H 0107

Interface sharpening in miscible Ni/Cu multilayers studied by atom probe tomography — •Zoltán Balogh, Mohammed Reda Chellali, Gerd-Hendrik Greiwe, and Guido Schmitz — Institut für Materialphysik, Westfälische Wilhelms Universität Münster; Münster (Germany)

The chemical analysis of buried interfaces is a delicate task that usually requires well conditioned specimens. The clear and gentle nature of field evaporation and the all 3D subnanometer resolution makes atom probe tomography a method with perspective in this field.

We investigated the effects of diffusional annealing in the miscible Ni/Cu system [1]. We prepared two kinds of samples. The first was produced with abrupt interfaces, while the second type revealed artificially smeared interfaces of about 3 nm in depth. After 15 min annealing at 773 K both types reveal an interface width in between the two different as-prepared values. Thus in the case of the smeared samples, the Ni/Cu interfaces sharpened even though the system is completely miscible at the annealing temperature. Another important observation is that the resulting interfaces were independent of the initial values.

Consequently even though thermodynamic equilibrium predicts infinite continous mixing at the interface, the actual kinetic process, determined by material transport properties, can require nevertheless finite sharpness in intermediate stages.

[1] Z. Balogh, M.R. Chellali, G.-H. Greiwe and Guido Schmitz, Appl. Phys. Lett. 99 (2011) 181902