MOSSBAUER INVESTIGATION OF THE GROWTH OF THE FE MULTILAYER IN FE(100)/AG(100) STRUCTURES

A monolayer of Fe57 is used as a probe layer in molecular-beam-epitaxy- grown Ag/Fe(001)/Ag(001) structures. Different Fe sites can be distinguished in the iron multilayer based on the isomer-shift (i.s.) and quadrupole-splitting (QS) values of different components in the Mössbauer spectrum. This makes it possible to determine the concentration of Fe57 atoms in the different atomic Fe layers and obtain information about the growth processes for different regions of the Fe multilayer. It was found that after deposition of about 5-Fe ML the growth changes from a Fe multilayer formation mode to a quasi-layer-by-layer mode. The values of the i.s. and QS are the same for Fe atoms located at the top and bottom Ag/Fe interface. Hhf values, on the other hand, are different by 9 kOe at the top and bottom for a sample in which the upper Ag(001) layer is covered by another Fe(001) layer. This result may be due to a contribution to the top Hhf value from Ruderman-Kittel-Kasuya-Yosida-like spin-density oscillations that couple the ferromagnetic Fe multilayers across the nonmagnetic Ag spacer. © 1995 The American Physical Society.