کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5370112 1388475 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermo-stimulated surface segregation in the ordering alloy Pt80Co20(1 1 1): Experiment and modeling
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Thermo-stimulated surface segregation in the ordering alloy Pt80Co20(1 1 1): Experiment and modeling
چکیده انگلیسی

In this paper, a method of Ionization Spectroscopy (IS) is proposed for the non-destructive layer-by-layer analysis of the elemental composition of a solid surface. Using ionization energy loss spectra, a layer-by-layer concentration profile of the Pt80Co20(1 1 1) alloy surface is obtained for different annealing temperatures. For the disordered Pt80Co20(1 1 1) at room temperature, the first atomic layer consists of pure Pt with damped oscillations in the deeper layers. Heating the sample reduces the oscillations. However, at a temperature of 823 K, a sandwich-like structure of the type Pt/Co/Pt was found in the first three atomic layers. For the ordered state the first atomic layer also consists of pure Pt with bulk concentration in other layers. LEED analysis shows a p(2 × 2) superstructure for the surface of the ordered Pt80Co20(1 1 1) alloy. The segregation behavior in this alloy is further studied by Monte Carlo (MC) simulations combined with the Constant Bond Energy (CBE) model. The results of the MC simulations agree well with the experiments at the higher temperatures, both for the surface composition and the concentration depth profile. At lower temperatures, some discrepancies exist between the MC results and the measured concentration profile.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Surface Science - Volume 253, Issue 3, 30 November 2006, Pages 1081-1089
نویسندگان
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