Characterization of Ni80Fe20/Cu multilayers by X-ray reflection using anomalous scattering

Meyer DC, Richter K, Wehner B, Reiss G, van Loyen L, Paufler P. Characterization of Ni80Fe20/Cu multilayers by X-ray reflection using anomalous scattering. In: EUROPEAN POWDER DIFFRACTION, PTS 1 AND 2. Vol 321-3. TRANS TECH PUBLICATIONS LTD; 2000: 451-456.Ni80Fe20/Cu muitilayers (Ni80Fe20=Py) belong to the sample systems, which show a Giant Magneto Resistance (GMR) interesting for magneto-electronic applications. The magnetic exchange coupling and thus the GMR depend sensitively on the layer structure and on the conditions of deposition. Regarding the structure characteristic correlation still clearing-up need exists. The composition of the layers from elements, which are neighbored in the periodic system of the elements, makes it necessary to use anomalous scattering conditions for the characterization by X-ray reflectometry. Therefore experiments were done with synchrotron radiation. Layer thickness, density of the layers and roughness of interfaces have been determined by fitting model parameters to the reflection curves. From fluorescence EXAFS measurements (Extended X-ray Absorption Fine Structure) near the Fe-K, Ni-K and Cu-K absorption edges the conclusion has been drawn that radial distributions of atoms in the thin layers correspond to those of compact polycrystalline material. Differences of the GMR values of the investigated samples can be attributed exclusively to the layer thickness and thickness relations, while influences of the roughness of the interfaces and structural differences play a subordinate role