Chemistry Reference
In-Depth Information
(a)
(b)
10 nm
10 nm
5 nm
0.35 nm
10 nm
10 nm
0.35 nm
10 nm
(a)
(b)
Fig. 5.6 RT
57
Fe Mössbauer absorption spectra for Fe/Mn interfaces. Sample structures are
illustrated in the figure. (a) and (b) show the situations of Mn-on-Fe and Fe-on-Mn interfaces,
respectively [
24
]
Figure
5.6
shows the Mössbauer spectra at 300 K to study two kinds of Fe/Mn
interfaces. Sample A was prepared by depositing
56
Fe,
57
Fe and Mn succeedingly,
while Sample B, Mn,
57
Fe and
56
Fe, one after another, on a Mylar substrate and the
deposition of the unit structure respectively was repeated for 30 times. Namely
Sample A exhibits the situation of Mn-on-Fe, while Sample B, that of Fe-on-Mn.
The nominal thickness of 0.35 nm corresponds to about 2 monolayers of Fe in the
interface region with Mn. The spectrum for Sample A is a 6-line pattern suggesting
that the interface region is entirely ferromagnetic. The line broadening is caused by
hyperfine field distribution in a certain degree indicating the existence of a minor
fraction with smaller hyperfine field. Each Fe atom in the topmost interface layer
has a few Mn neighbor atoms and accordingly the hyperfine field should be
reduced. Although the 6-line pattern is fairly broad, the chemical mixing or
interdiffusion at the Fe/Mn interface in Mn-on-Fe sample has not very much taken
