Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 38: Magnetic Nanoparticles
MA 38.4: Vortrag
Donnerstag, 19. März 2015, 10:15–10:30, H 0110
A unique multiple-twinned, chemically ordered FePt nanocrystal observed by transmission electron microscopy — •Zi-An Li1, Marina Spasova1, Quentin Ramasse2, Markus Gruner1, Christian Kisielowski3, and Michael Farle1 — 1Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE), University Duisburg-Essen, Germany — 2SuperSTEM Laboratory, STFC Daresbury Campus, United Kingdom — 3National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, University of California, USA
Using a combination of high-resolution transmission electron microscopy (HRTEM) and high angle annular dark field (HAADF) imaging in scanning transmission electron microscopy (STEM), we characterize the crystal structure of multiple-twinned FePt nanocrystals produced by gas-phase condensation. These FePt nanocrystals are found to be chemically ordered, decahedral or icosahedral shaped, and Pt enriched at the surfaces. [1,2] The experimentally determined crystallographic lattice constants and distribution of Fe and Pt atoms are compared with first-principles calculations of FePt nanocrystals to confirm the discovery of a unique multiple-twinned structure with Fe/Pt ordering and Pt surface segregation. References: 1. Zi-An Li, et al. Phys. Rev. B 89, 161406(R) (2014). 2. Financial support by ERC- Grant *IMAGINE* is acknowledged.