抄録
It is still open to question whether the very strong interlayer coupling in Fe/Si superlattices is mediated by amorphous Si (a-Si) or crystalline silicides. To clarify this problem, we performed precise structural characterization of the layered structures, and found that the silicide spacer, not a-Si, causes the coupling between adjacent Fe layers. This conclusion was also supported by two kinds of experiment. The coupling state of a non-coupled Fe/Si superlattice with thick Si spacers changed from a non-coupled state to an antiferromagnetic state and further to a ferromagnetic state as the annealing promoted interdiffusion at Fe/Si interfaces. Furthermore, a very strong and nearly perfect antiferromagnetic coupling was found in Fe/Fe-73 at %Si superlattices. These results support our conclusion that the strong interlayer coupling in Fe/Si superlattices is mediated by the formation of crystalline silicide in the spacers.
