Structure and Interlayer Magnetic Coupling in Fe/Si Multilayers.

Abstract

This paper studies Fe/Si multilayers having semiconductor spacers, which are expected to have.a peculiar character not observed in metallic multilayers. It was demonstrated that there are two types of antiferromagnetic interlayer couplings with different origins depending on Si layer thickness in (Fe 2.6 nm/Si tsi nm)22. One was observed around tsi=1.2 nm at RT and converted into a ferromagnetic coupling at a low temperature, and the other was observed at tsi>1.2 nm with a minimum around 2.5 nm and almost tempereture-independent, The first negative magnetoresistance (MR)associated with antiferromagnetic coupling was also observed in Fe/Si multilayers. We inferred that the spacer intervening in the former coupling is a semiconducting FeSi phase formed in the interface and, in the latter coupling an amorphous Si with variable-range hopping-type conductivity.