Surface-segregation-induced phase separation in epitaxial Au/Co nanoparticles: Formation and stability of core-shell structures

Sato, Kazuhisa; Matsushima, Yuta; Konno, Toyohiko J.

AIP Advances, 2017, 7(6), 065309

Number of Access:394（2025-08-14 03:09 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/89411

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Title
Surface-segregation-induced phase separation in epitaxial Au/Co nanoparticles: Formation and stability of core-shell structures
Creator
NRID
1000070314424 1000070314424
ORCID
0000-0001-9078-2541 0000-0001-9078-2541
researchmap permalink
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Scopus Author ID
55552977400 55552977400
CreatorName
Sato, Kazuhisa
CreatorName
Matsushima, Yuta
NRID
1000090260447 1000090260447
CreatorName
Konno, Toyohiko J.
Description
Kazuhisa Sato, Yuta Matsushima, and Toyohiko J. Konno, "Surface-segregation-induced phase separation in epitaxial Au/Co nanoparticles: Formation and stability of core-shell structures", AIP Advances 7, 065309 (2017).
Abstract
We have studied formation and stability of core-shell structures in epitaxial Au/Co nanoparticles (NPs) by using atomic-resolution scanning transmission electron microscopy. As the particle size reduces, number of NPs having Au-shell increases and their frequency of occurrence reached 65%. Au segregation proceeds during particle growth at 520 K. The core-shell structure formation is particle size-dependent; the critical diameter dividing the Au-shell and the Co-shell structures is about 11 nm, below which the Au-shell is stable. After annealing at 800 K for 3.6 ks, Au-shell NPs were conserved while the Co-shell NPs changed to two-phase structures with a planar interface separating Au and Co. There is a local energy minimum where the Co-shell NP is metastable in the as-deposited state. A simple model based on surface and interfacial energies suggests stability of Au-shell structures. Surface-segregation-induced phase separation in small NPs, due to low surface free energy of Au, will be responsible for the Au-shell formation.
Publisher
American Institute of Physics
Source Title
AIP Advances
Volume (Issue)
7(6)
Page
065309
Date of Issued
2017-06
Language
English
Handle URL
https://hdl.handle.net/11094/89411
eISSN
21583226
Relation.isIdenticalTo
DOI (Publisher Version)
https://doi.org/10.1063/1.4986905
Access Rights
open access
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This article is licensed under a Creative Commons Attribution 4.0 International License.
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Category
学術雑誌論文 Journal Article