The Antiferromagnetic Coupling And Interface Diffusion In Fe/Si Multilayers

The antiferromagnetic coupling in Fe/Si multilayers has been observed in 1990s. Its mechanism has been investigatede since then. But the understanding of its mechanism has been controversial until now. This paper has discussed the influence of the interface diffusion on the antiferrimagnetic(AF) coupling by annealing and doping on the basis of the research of the AF coupling in Fe/Si multilayers.The Fe/Si multilayers with spacers varying from pure Si to heavy doped n-type and p-type Si have been prepared by magnetron sputtering. It is confirmed that these multilayers have the same AF coupling which have been depicted in reference papers. The large-angle x-ray diffraction data of as-made samples show that 2θ of diffracton peak of Fe in multilayers is bigger than in bulk, and annealed samples have bigger 2θ than as-made. Comparing the low-angle x-ray diffraction data of as-made and annealed samples, It is observed that annealed sample have smaller 2θ than as-made. The intensity of the AF coupling of the samples which have been annealed at 150℃ is the same as that of as-made. So it is found that interlayer diffusion between Fe and Si occurred, and the diffusion overwhelmed the heavy doping of Si, which made no difference at all for the AF coupling with different type Si. Furthermore, the AF coupling in Fe/Si multilayers still goes on while the diffusion between Fe and Si layers increases and the layer structure is degraded to some extent after annealing.The Fe/Si1-xCrx multilayers have been prepared. With x creasing, the intensity of the AF coupling in multilayers becomes weak. The large-angle x-ray diffraction data show that the interface diffusion is prevented due to doping. And doping destroys the structure of multilayers in the basis of the low-angle x-ray diffraction data. So it is found that the interface diffusion is a important factor influencing the AF coupling.