JMMM 118 (1993) 99-109

Magnetic order near Fe(100) interfaces from Mossbauer spectroscopy

G. Liu and U. Gradmann

Magnetic hyperfine fields B_hf near W(100)/Fe(100) and Fe(100)/Ag 
interfaces were analyzed with monolayer resolution by conversion electron 
Mossbauer spectroscopy (CEMS) in situ in UHV of epitaxial Fe(100) films on 
W(100), probed with Fe-57 monolayers. Strongly reduced values of B_hf near 
W(100) can be explained using data from Fe/W alloys; a spatial oscillation 
of B_hf is observed for this interface. Spin-wave parameters in the first 
monolayer are enhanced by a factor of 2.6 in the Fe/W and by a factor of 
3.1 in the Fe/Ag interface, respectively, indicating a moderate reduction 
of exchange in this interface. A previously reported large reduction in 
exchange interactions in the free interface could not be confirmed. In the 
first monolayer below Ag, two components of Fe are observed with different 
hyperfine fields.