Composition and structure of the (100) and (110) surfaces of FeAl

• Published in: Surface science 1995, Vol.322 (1-3), p.103-115
• Main Authors: GRAUPNER, H, HAMMER, L, MÜLLER, K, ZEHNER, D. M
• Format: Article
• Language: English
• Subjects: Annealing; Auger electron spectroscopy; Composition; Composition; defects and impurities; Condensed matter: structure, mechanical and thermal properties; Crystal atomic structure; Evaporation; Exact sciences and technology; Iron alloys; Low energy electron diffraction; Morphology; Physics; Solid surfaces and solid-solid interfaces; Stoichiometry; Structure (composition); Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal effects
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(94)00626-1

The structure and composition of the (100) and (110) oriented surfaces of the ordered alloy FeAl were investigated by LEED and AES. Following sputtering and annealing, c(2mult2) and (1mult1) LEED patterns are observed on the (100) surface. The c(2mult2) is attributed to an ordered arrangement of Al atoms on top of a complete Fe layer, while the (1mult1) corresponds to the Al terminated surface, as determined previously. On the (110) oriented surface, a (2mult1) diffraction pattern, an incommensurate superstructure, and severe streaking are observed with LEED upon annealing. For the (2mult1) structure, a missing-row model is compatible with a stoichiometry of Fe sub 2 Al. The incommensurate superstructure and streak phase are associated with a near-surface aluminum concentration > "0.5, indicating segregation of Al. In contrast to the NiAl(110) surface, no (1mult1), which would indicate the formation of the bulk-like terminated surface, is observed with LEED. Annealing both surfaces over 800 deg C leads to evaporation of Al. Copyright (c) 1995 Elsevier Science B.V. All rights reserved.