Local atomic structure of Fe/Cr multilayers: Depth-resolved method

Abstract A depth-resolved method for the investigation of the local atomic structure by combining data of X-ray reflectivity and angle-resolved EXAFS is proposed. The solution of the problem can be divided into three stages: 1) determination of the element concentration profile with the depth z from X-ray reflectivity data, 2) determination of the X-ray fluorescence emission spectrum of the element i absorption coefficient μ i a ( z,E ) as a function of depth and photon energy E using the angle-resolved EXAFS data I i f ( E , ϑ l ) , 3) determination of partial correlation functions g ij ( z , r ) as a function of depth from μ i ( z , E ) . All stages of the proposed method are demonstrated on a model example of a multilayer nanoheterostructure Cr/Fe/Cr/Al 2 O 3 . Three partial pair correlation functions are obtained. A modified Levenberg-Marquardt algorithm and a regularization method are applied.