Segregation profile and surface structure of Pt35Co65(110): Pt25Co75(110) revisited

被引：22

作者：

Bugnard, JM ^{[1
]}

Gauthier, Y ^{[1
]}

BaudoingSavois, R ^{[1
]}

机构：

[1] CNRS,CRYSTALLOG LAB,F-38042 GRENOBLE 09,FRANCE

来源：

SURFACE SCIENCE | 1995年 / 344卷 / 1-2期

关键词：

alloys; cobalt; low energy electron diffraction (LEED); metallic surfaces; platinum; single crystal surfaces; surface relaxation and reconstruction; surface segregation;

D O I：

10.1016/0039-6028(95)00846-2

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We address the general question of segregation in deep layers of bimetallic alloys and crystal preparation by heat treatment. A new analysis of LEED I(V) spectra collected on an originally Pt25Co75(110) surface reveals that: (1) LEED is very sensitive to the bulk concentration and lattice parameter; (2) the bulk was enriched with Pt to form a Pt35Co65(110) alloy. The results obtained for the segregated surface layers differ very little from those assuming a 25% Pt substrate: the concentration in the five top layers are respectively 1, 99, 0, 55, 0% Pt. The first interlayer spacing is strongly reduced (-16%) with respect to the bulk value, the second one is expanded by about 10% and the third one is almost bulklike (-1.9%). For this bulk composition, no metastable state corresponding to a Pt-rich top layer is observed although the predictions from TBIM and EAM left this possibility as an open question.

引用

页码：42 / 50

页数：9

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