Magnetic and electronic properties of Fe/C multilayers: Interfacial effects

Abstract

Fe/C multilayers with different Fe thicknesses (tFe) were prepared using triode sputtering with a fixed C layer thickness of 20 Å, while the Fe film thickness was changed from 30 to 300 Å. The magnetization strongly decreases with decreasing tFe when tFe was smaller than 60 Å. This is attributed to the existence of a magnetically dead layer due to the presence of Fe1−xCx alloys at the Fe/C interface due to the diffusion of carbon in iron. First-principles calculations based on Density Functional Theory (DFT) were performed to investigate the magnetic and electronic structures of the interfacial Fe1−xCx alloys. It is shown that the C insertion reduces the magnetization, which becomes significant with increasing C content. In addition, the influence of pressure by changing volume on the magnetic properties was investigated as well, where the pressure reduces significantly the interfacial magnetization.