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Multiply Twinned Structures in Gas-Phase Sintered Stoichiometric FePt Nanoparticles

Published online by Cambridge University Press:  17 March 2011

Sonja Stappert ,
Bernd Rellinghaus ,
Mehmet Acet  and
Eberhard F. Wassermann
Sonja Stappert
Affiliation:
Experimentelle Tieftemperaturphysik and Sonderforschungsbereich 445, Gerhard-Mercator Universität, D-47048 Duisburg, Germany
Bernd Rellinghaus
Affiliation:
Experimentelle Tieftemperaturphysik and Sonderforschungsbereich 445, Gerhard-Mercator Universität, D-47048 Duisburg, Germany
Mehmet Acet
Affiliation:
Experimentelle Tieftemperaturphysik and Sonderforschungsbereich 445, Gerhard-Mercator Universität, D-47048 Duisburg, Germany
Eberhard F. Wassermann
Affiliation:
Experimentelle Tieftemperaturphysik and Sonderforschungsbereich 445, Gerhard-Mercator Universität, D-47048 Duisburg, Germany
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Abstract

Stoichiometric FePt nanoparticles with sizes in the range 3 – 6 nm were prepared in the gas-phase and thermally sintered prior to deposition. Whereas unsintered particles exhibit irregular shapes and a low degree of crystallinity, the majority of the sintered particles are multiply twinned and have predominantly icosahedral structure. There is no indication for the occurance of L10 ordering in the gas-phase sintered particles, although previous post-deposition annealing experiments of unsintered particles had shown the occurrence of partial formation of the L10 FePt intermetallic phase. On the other hand, analysis of the structural data obtained from (high resolution) electron microscopy shows that the relative amount of icosahedral particles increases with increasing sintering temperature. This result is discussed on the basis of a structure model of an irregular icosahedron, which is built up from distorted tetrahedral building blocks. The distortion in each tetrahedron is in accordance with the tetragonally compressed unit cell of the L10-phase.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 704: Symposium W – Nanoparticulate Materials , 2001 , W5.7.1
Copyright
Copyright © Materials Research Society 2002

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