Investigation of Au and Ag segregation on Fe(001) with soft X-ray absorption

We investigated the X-ray absorption at the Fe L3 edge of Fe grown on Cr(001), Au(001) and Ag(001). Systematic variations in the absorption were observed depending on the nature of the buffer. They are explained by segregation of Au and Ag during Fe deposition at room temperature. By measuring wedge shaped samples, the segregated amounts could be measured. Taking into account the possible influence of roughness, we find that the segregated amounts of Au and Ag on a 1 nm-thick Fe film are 0.8 ± 0.3 ML and 2.0 ± 0.3 ML, respectively.