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Metastable phase formation of Pt-X (X = Ir, Au) thin films

The dependence of phase formation and mechanical properties on the chemical composition has been investigated for Pt-Ir and Pt-Au combinatorial thin films. The formation of a single, metastable Pt-Ir solid solution has been observed for all experimental compositions and temperatures. Upon Ir additio...

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Autores principales: Saksena, Aparna, Chien, Yu-Chuan, Chang, Keke, Kümmerl, Pauline, Hans, Marcus, Völker, Bernhard, Schneider, Jochen M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033916/
https://www.ncbi.nlm.nih.gov/pubmed/29977046
http://dx.doi.org/10.1038/s41598-018-28452-4
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author Saksena, Aparna
Chien, Yu-Chuan
Chang, Keke
Kümmerl, Pauline
Hans, Marcus
Völker, Bernhard
Schneider, Jochen M.
author_facet Saksena, Aparna
Chien, Yu-Chuan
Chang, Keke
Kümmerl, Pauline
Hans, Marcus
Völker, Bernhard
Schneider, Jochen M.
author_sort Saksena, Aparna
collection PubMed
description The dependence of phase formation and mechanical properties on the chemical composition has been investigated for Pt-Ir and Pt-Au combinatorial thin films. The formation of a single, metastable Pt-Ir solid solution has been observed for all experimental compositions and temperatures. Upon Ir addition to Pt the experimentally determined changes in lattice parameter and Young’s modulus display rule of mixture behavior which is in good agreement with our ab initio data. Whereas, in the Pt-Au system, the single metastable solid solution decomposes into two phases as the growth temperature is raised to ≥600 °C. The lattice parameters in the dual phase region are independent of chemical composition. The substrate temperature and chemical composition dependent phase formation in Pt-Ir and Pt-Au thin films can be rationalized based on CALPHAD (CALculation of PHAse Diagrams) results combined with estimations of the activation energy required for surface diffusion: The metastable phase formation during film growth is caused by kinetic limitations, where Ir atoms (in Pt-Ir) need to overcome an up to factor 6 higher activation energy barrier than Au (in Pt-Au) to enable surface diffusion.
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spelling pubmed-60339162018-07-12 Metastable phase formation of Pt-X (X = Ir, Au) thin films Saksena, Aparna Chien, Yu-Chuan Chang, Keke Kümmerl, Pauline Hans, Marcus Völker, Bernhard Schneider, Jochen M. Sci Rep Article The dependence of phase formation and mechanical properties on the chemical composition has been investigated for Pt-Ir and Pt-Au combinatorial thin films. The formation of a single, metastable Pt-Ir solid solution has been observed for all experimental compositions and temperatures. Upon Ir addition to Pt the experimentally determined changes in lattice parameter and Young’s modulus display rule of mixture behavior which is in good agreement with our ab initio data. Whereas, in the Pt-Au system, the single metastable solid solution decomposes into two phases as the growth temperature is raised to ≥600 °C. The lattice parameters in the dual phase region are independent of chemical composition. The substrate temperature and chemical composition dependent phase formation in Pt-Ir and Pt-Au thin films can be rationalized based on CALPHAD (CALculation of PHAse Diagrams) results combined with estimations of the activation energy required for surface diffusion: The metastable phase formation during film growth is caused by kinetic limitations, where Ir atoms (in Pt-Ir) need to overcome an up to factor 6 higher activation energy barrier than Au (in Pt-Au) to enable surface diffusion. Nature Publishing Group UK 2018-07-05 /pmc/articles/PMC6033916/ /pubmed/29977046 http://dx.doi.org/10.1038/s41598-018-28452-4 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Saksena, Aparna
Chien, Yu-Chuan
Chang, Keke
Kümmerl, Pauline
Hans, Marcus
Völker, Bernhard
Schneider, Jochen M.
Metastable phase formation of Pt-X (X = Ir, Au) thin films
title Metastable phase formation of Pt-X (X = Ir, Au) thin films
title_full Metastable phase formation of Pt-X (X = Ir, Au) thin films
title_fullStr Metastable phase formation of Pt-X (X = Ir, Au) thin films
title_full_unstemmed Metastable phase formation of Pt-X (X = Ir, Au) thin films
title_short Metastable phase formation of Pt-X (X = Ir, Au) thin films
title_sort metastable phase formation of pt-x (x = ir, au) thin films
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033916/
https://www.ncbi.nlm.nih.gov/pubmed/29977046
http://dx.doi.org/10.1038/s41598-018-28452-4
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