Surface segregation in nanoparticles from first principles: The case of FePt

SCRIPTA MATERIALIA

卷:62

Article

Chepulskii, Roman V.¹  Butler, W. H.²  van de Walle, A.³  Curtarolo, Stefano¹ 

[1] Duke Univ, Dept Mech Engn & Mat Sci, Durham, NC 27708 USA

[2] Univ Alabama, Ctr Mat Informat Technol, Tuscaloosa, AL 35487 USA

[3] CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA

关键词: Nanocrystalline materials;    Magnetic anisotropy;    Surface segregation;    Monte Carlo techniques;    Cluster expansion;   

DOI  :  10.1016/j.scriptamat.2009.10.019

来源: Elsevier

【 摘 要 】

FePt nanoparticles are known to exhibit reduced L 1(0) order with decreasing particle size. The phenomenon is addressed by investigating the thermodynamic driving forces for surface segregation using a local (inhomogeneous) cluster expansion fit to ab initio data. Subsequent Monte Carlo simulations reveal that first surface layer Pt segregation is compensated by Pt depletion in the second subsurface layer. This indicates that the core's ordered state is not affected by surface thermodynamics as much as previously thought. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

【 授权许可】

Free