ALLOYING EFFECTS ON X-RAY-ABSORPTION EDGES IN PT1-XNIX SINGLE-CRYSTALS

Electronic structure modifications of platinum and nickel produced by alloying these two metals were studied on a series of single crystals of different composition by X-ray absorption spectroscopy, using synchrotron radiation. Both Pt and Ni absorption edges show simultaneous structure changes. These modifications are located mainly several electronvolts above the Fermi level. The variation in hole number in the Pt 5d band was estimated by several analysis methods which all conclude to an electron transfer from nickel to platinum. Conversely, the modifications observed on the Ni K edge are situated at the neighborhood of E(f) and are interpreted as a population rearrangement between 3d,4s, and 4p levels. These observations are finally discussed by comparison with photoemission results and published calculations of density of states.