Static atomic displacements in the near-surface region of the Invar alloy Fe-28 at.% Pt

Abstract Diffuse scattering under grazing incidence of a Fe-27.8 at.% Pt (110) surface was measured at RT and 424 K to explore the impact of the Invar behavior in the near-surface region. The quenched-in short-range order does not change between these two temperatures. The presence of an oscillatory segregation profile is indicated through a directional dependence of the nearest-neighbor site occupation. Size-effect scattering is found to be lower at RT than at 424 K. The species-independent displacement parameters of the nearest and next-nearest neighboring shells are larger than in the bulk, their change with temperature shows the same behavior as in the bulk. This analogous behavior of the near-surface microstructure to the bulk is a strong support that the Invar behavior is retained in the near-surface region.