Crystallographic structure of ultrathin Fe films on Cu(100).
We report the observation of bcc-like crystal structures in 2-4 monolayer (ML) Fe films grown on fcc Cu(100) using scanning tunneling microscopy. The local bcc structure provides a straightforward explanation for their frequently reported outstanding magnetic properties, i.e., ferromagnetic ordering in all layers with a Curie temperature above 300 K. The nonpseudomorphic structure, which becomes pseudomorphic above 4 ML film thickness, is unexpected in terms of conventional rules of thin film growth and stresses the importance of finite thickness effects in ferromagnetic ultrathin films.
Biedermann
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Institut für Allgemeine Physik, Vienna University of Technology, A-1040 Vienna, Austria.
Tscheliessnig
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R
Schmid
M
M
Varga
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P