Magnetic and Mössbauer study of Fe/Si multilayers

Abstract

The magnetic and structural properties of Fe/Si multilayers (Mls) have been studied by x-ray diffraction (XRD) and conversion electron Mössbauer spectroscopy (CEMS) methods. Strong antiferromagnetic (AF) coupling J=−1.93 mJ/m2 accompanied by saturation field of 1.5 T has been found for Si layer thickness dSi=1.4 nm. Magnetic moment measurements of Fe/Si Mls vs Fe thickness revealed that 0.25 nm of Fe per single interface is magnetically inactive. The CEMS spectra recorded at room temperature consist of the Zeeman sextet characteristic of the pure Fe phase (hyperfine field of about 32.8 T) accompanied by two spectral components related to FeSi system: magnetic broad sextet and a quadrupole doublet. The broad sextet could originate from various Fe sites at the interface. The nonmagnetic quadrupole split (QS) doublet is most probably associated with the nonstoichiometric c-Fe1−xSix phase. For larger Si layer thickness (dSi>2 nm) the spectral contribution of the QS doublet increases from 5.7% to about 16%.