Natural Oxidation of thin Fe Films on V Buffer Layer

Abstract

We have studied oxidation kinetics of Fe thin film under atmospheric conditions using the fact that metallic iron is a ferromagnet but ultrathin natural iron oxides are approximately nonmagnetic at room temperature. As a consequence, oxidation is associated with a loss in total Fe magnetic moment. Results show that the sample with an initial Fe thickness equal to 10 nm oxidize relatively fast (time constant τ = 0.05 day), whereby a constant amount of 2.5 nm of metal is transformed into oxides. For lower iron initial thickness (di = 4 nm) the time constant for oxidation significantly increases reaching a value of 2 days. Furthermore, X-ray photoelectron spectroscopy studies performed after 144 days of oxidation revealed formation of hematite (α-Fe2O3) thin film on the metallic rest of iron.

Magnetic exchange interactions and phase transition in Fe/V(100), V/Fe/V(100) and Fe/V/Fe/V(100) films

“…The lattice mismatch between Fe (2.75Å) and V (3.02Å) is about 10% and it is observed that Fe films can be grown on V(100) epitaxially with little intermixing at the interface [12]. Very recently, it has been reported that the Fe films on V grow in planar mode upto a thickness of 5 nm (more than 25 Fe layers) [13]. This makes the Fe/V films an attractive candidate for the study of interrelation between structure and magnetism.…”

“…There are many interesting experimental observations [6,7,[13][14][15][16][17][18] for Fe/V films. It is found that the magnetic moments on the Fe layers set in when the Fe film thickness becomes two monolayers thick and thereafter, the magnetic moments on the Fe layers increase linearly with the Fe film thickness.…”

“…Theoretical calculations on FePt films suggest that the magnetic anisotropy as well as the exchange interactions, and so the nature of magnetic order can be affected by lattice relaxation effects [24,[32][33][34]. Experiments on Fe/V systems show that the Fe films grow on V(100) epitaxially with little intermixing at the interface [12] and that the Fe films on V grow in planar mode upto a thickness of 5 nm (more than 25 Fe layers) [13]. Therefore, it is obvious that different Fe layers will have different lattice parameters resulting in lattice strain.…”