Regensburg 2004 – wissenschaftliches Programm
O 27.1: Hauptvortrag
Mittwoch, 10. März 2004, 15:15–16:00, H1
Stress on the atomic scale: From surface reconstruction to stress oscillations and magnetostriction of atomic layers — •Dirk Sander — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle
Mechanical stress is an important factor, which governs a number of fundamental aspects in surface science, film growth, and magnetic anisotropy. Examples are e.g. the surface reconstruction of clean and adsorbate-covered surfaces, oscillatory stress relaxation in nanosize islands, and the magnetoelastic coupling in ferromagnetic monolayers. Stress measurements by the cantilever bending technique are presented for each example. Film stress in the GPa range, in excess of the tensile strength of high-strength materials, is measured for epitaxially strained layers. Structural relaxation due to island growth and coalescence, and surface alloy formation are comparatively subtle effects, which are detected by the respective stress signature. The in situ combination of stress measurements during film growth with magnetoelastic stress measurements upon magnetization reversal identifies a strain-induced change of the magnetoelastic coupling constants from the respective bulk value. The impact on the peculiar magnetic anisotropy of ferromagnetic layers is discussed.