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A mechanism of inhibition of phase transitions in nano-grained close-packed Pd thin films

SYSNO ASEP	0350404
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	A mechanism of inhibition of phase transitions in nano-grained close-packed Pd thin films
Author(s)	Hüger, E. (DE) Káňa, Tomáš (UFM-A)_{RID, ORCID} Šob, Mojmír (UFM-A)_{RID, ORCID}
Number of authors	3
Source Title	Calphad - Computer Coupling of Phase Diagrams and Thermochemistry. - : Elsevier - ISSN 0364-5916 Roč. 34, č. 4 (2010), s. 421-427
Number of pages	7 s.
Language	eng - English
Country	GB - United Kingdom
Keywords	phase transformations ; thin films ; nanocrystalline materials
Subject RIV	BM - Solid Matter Physics ; Magnetism
R&D Projects	IAA100100920 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR)
	OC10008 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
CEZ	AV0Z20410507 - UFM-A (2005-2011)
UT WOS	000285327700006
DOI	doi:10.1016/j.calphad.2010.07.009
Annotation	Analyzing experimental data and calculating corresponding energy barriers from first principles, we elucidate the feasibility of the experimentally observed phase transformation between the hcp and double hcp (dhcp) structures in the hcp Pd thin films grown on W(001) and Nb(001) substrates and absence of the hcp-fcc transformation in those films. The hcp-dhcp transformation can be modeled by a transformation path which preserves the existing domain topology of the films and exhibits a sufficiently low energy barrier. On the other hand, this orthogonal pattern of rectangular domains induced by the fourfold symmetry of the substrate surface hinders the hcp Pd phase to convert back to the ground-state fcc phase, although there exists a transformation path exhibiting a very low energy barrier between the hcp and fcc structures. This path, however, would break the domain arrangement and, therefore, it cannot be accomplished. In this way, the hcp crystalline phase is locked inside of nanograins.
Workplace	Institute of Physics of Materials
Contact	Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485
Year of Publishing	2011

Number of the records: 1