Oxidation Kinetics of Thin and Ultrathin Fe Films
A. Marczyńskaa, J. Skoryna a, M. Lewandowski b and L. Smardz a
aInstitute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
bNanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
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We have studied oxidation kinetics of Fe thin films under atmospheric conditions using the fact that metallic iron is a ferromagnet but ultrathin natural iron oxides are practically nonmagnetic at room temperature. As a consequence, oxidation is associated with a loss in ferromagnetism. Fe thin films were deposited onto 1.5 nm V thick buffer layer using UHV magnetron sputtering. As a substrate we have used Si(100) wafers with an oxidised surface. Results show that all samples with an initial Fe thickness greater than 6 nm oxidize practically instantaneously, whereby a constant amount of 2.5 nm of metal is transformed into oxides. For iron thickness lower than 6 nm the time constant for oxidation increases considerably reaching a value of 30 days for the initial Fe thickness equal to 4 nm.

DOI: 10.12693/APhysPolA.127.549
PACS numbers: 75.70.-i, 68.55.-a