Regensburg 2000 – wissenschaftliches Programm

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AM: Magnetismus

AM 15: Oberflächenmagnetismus: Struktur und Wachstum, Anisotropie

AM 15.4: Vortrag

Mittwoch, 29. März 2000, 14:45–15:00, H22

Suppression of silicide formation in Fe/Si(100) — •F. Zavaliche, W. Wulfhekel und J. Kirschner — MPI für Mikrostrukturphysik, Weinberg 2, 06120 Halle

We report on the morphology and magnetic properties of thin Fe films grown at room and low temperatures (150 K) on (2x1) and on Au-passivated Si(001). In the case of Fe grown on (2x1) Si(001), the magnetization sets in at an Fe coverage of 3.6 monolayers (ML) at room temperature (RT) and of 2.3 ML at 150 K. Silicide formation at the Fe-Si interface strongly reduces the magnetization in these cases. To suppress intermixing we grew a 2 ML thick Au buffer layer by depositing about 0.5 ML of Au at ≈1000 K, followed by the deposition of another 1.5 ML at RT or at 150 K. Growth of 0.5 ML of Au at ≈1000 K results in a complex reconstruction of Si(001). Au deposited at RT gives rise to rough buffer layers and does not lead to an earlier onset of magnetization in the Fe films. However, at 150 K, smooth Au buffer films are obtained, acting as protective layers against Fe and Si intermixing. In both cases, a strong out-of-plane magnetization is measured at the onset coverages. Growth of Fe films at 150 K on buffer layers results in an earlier onset of the out-of-plane magnetization, i.e. at 1.4 ML, pointing at a significant reduction in the silicide formation. The thermal stability of a 2.3 ML thick Fe film grown at 150 K on Au-covered Si(001) is proven by its reversible magnetic behavior upon annealing to 280 K and cooling back to 150 K.