Surface structure of stepped NiAl(111) by low energy Li sup + ion scattering

Journal Article · Mon Jan 01 00:00:00 EST 1990 · Surface Science; (Netherlands)

DOI:https://doi.org/10.1016/0039-6028(90)90766-2· OSTI ID:7295064

Overbury, S H; Mullins, D R; Wendelken, J F ^[1]

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1. Oak Ridge National Lab., TN (United States)

Previous LEED and ISS studies have indicated that there are equal amounts of Ni and Al terminated domains on the (111) surface of the strongly ordered NiAl alloy. However, a study of the energy dependent broadening of LEED beams diffracted from a stepped NiAl(111) surface indicates that there is a preference for double step heights suggesting that high step density may impose termination in only one type of domain. The authors have now measured the angle dependence of Li{sup +} scattering from stepped NiAl(111) surface cut 1.7 from the (111) orientation. Scattering along the (121) and (211) azimuths permit conditions where only the first layer or where a sum of first and second layer scattering is observed. By analysis of the Ni and Al intensities from first and second layer scattering is observed. By analysis of the Ni and Al intensities from first and second layers and comparison with previous ion scattering results on NiAl(110), it is found that the equilibrium stepped surface terminates with roughly equal amounts of both types of domains. The angle dependence of the ion scattering confirms the bulk terminated surface structure with first layer relaxation. The incidence angle associated with the onset of second layer scattering from Ni and Al can be used to determine the first inter-layer spacing for each type of domain independently. The measured spacings confirm previous LEED results for the low index surface that the first layer spacing differs in magnitude for the two different terminations.

• OSTI ID: 7295064
• Journal Information: Surface Science; (Netherlands), Vol. 236; ISSN 0039-6028
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRYSTAL STRUCTURE
NICKEL ALLOYS
ANGULAR DISTRIBUTION
COMPARATIVE EVALUATIONS
ELECTRON DIFFRACTION
EXPERIMENTAL DATA
LITHIUM IONS
MILLER INDICES
SCATTERING
SURFACES
ALLOYS
CHARGED PARTICLES
COHERENT SCATTERING
DATA
DIFFRACTION
DISTRIBUTION
EVALUATION
INFORMATION
IONS
NUMERICAL DATA
360102* - Metals & Alloys- Structure & Phase Studies