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C. Bréchignac Ph. Cahuzac F. Carlier C. Colliex M. de Frutos N. Kébaïli J. Le Roux A. Masson B. Yoon 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):265-268
We studied shape relaxation of nano-fractal islands,
during annealing, after their growth from antimony cluster
deposition on graphite surface. Annealing at
180°C shows evidence of an increase
of the fractal branch width with time followed by branch
fragmentation, without changing the fractal dimension. The time
evolution of the width of the arm suggests the surface
self-diffusion mechanism as the main relaxation process. With
Monte Carlo simulations, we confirmed the observed behavior.
Comparison is done with our previous results on fragmentation of
nano-fractal silver islands when impurity added to the incident
cluster promotes rapid fragmentation by surface self-diffusion
enhancement [1]. 相似文献
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Bréchignac C Cahuzac P Carlier F Colliex C Leroux J Masson A Yoon B Landman U 《Physical review letters》2002,88(19):196103
Formation and evolution of fragmentation instabilities in fractal islands, obtained by deposition of silver clusters on graphite, are studied. The fragmentation dynamics and subsequent relaxation to the equilibrium shapes are controlled by the deposition conditions and cluster composition. Sharing common features with other materials' breakup phenomena, the fragmentation instability is governed by the length-to-width ratio of the fractal arms. 相似文献
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Kociak M Stéphan O Henrard L Charbois V Rothschild A Tenne R Colliex C 《Physical review letters》2001,87(7):075501
We report on the investigation of surface-plasmon excitation of anisotropic WS(2) hollow nanoparticles in a near-field geometry by means of a scanning transmission electron microscope. The shell thickness influence on the electron-energy-loss-spectroscopy spectra is experimentally observed and is analyzed within a classical dielectric formalism. As for the isotropic case, we evidence one symmetric (tangential) and one antisymmetric (radial) mode. We point out the intriguing fact that, for the anisotropic case, one can relate these modes to the interband transition of the in-plane component of the dielectric tensor and to the bulk-plasmon energy of the out-of-plane component. 相似文献
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C. Bréchignac Ph. Cahuzac F. Carlier C. Colliex M. de Frutos N. Kébaïli J. Le Roux A. Masson B. Yoon 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):265-269
The deposition of preformed clusters on surfaces has been established as a new way for growing nano-suctures on surfaces.
It has been shown that supported island morphology relies on the dynamics of clusters, during the growth, giving rise to shapes
from compact to ramified types. This paper identifies and discusses, in the case of antimony cluster deposits, several processes
responsible for the non-equilibrium island shapes: limited kinetic cluster aggregation, size dependent coalescence, “wetting-like
behavior” of antimony clusters on antimony islands. Using successive predetermined cluster sizes during the deposition process
to synthesize polymorphic structure involves the interplay of those mechanisms.
Received 1st December 2000 相似文献
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Mobility and aggregation of free clusters soft landed on amorphous and crystalline carbon substrates
C. Bréchignac Ph. Cahuzac F. Carlier M. de Frutos A. Masson C. Colliex C. Mory B. Yoon 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,40(1):516-519
Neutral antimony clusters produced by a gas aggregation source have been deposited at room temperature on thin films of amorphous carbon and cleavage surfaces (0001) of graphite. Antimony islands generated from different mean size distributions of preformed clusters Sbn(n = 4, 90, 150, 250, 600, 2000) have been investigated by transmission electron microscopy. Only compact islands have been observed on amorphous carbon, whereas an evolution from compact to dendritic shapes occurs on graphite substrate as the mean size of the deposited clusters increases. For clusters containing more than 150 atoms the dendritic islands exhibit a fractal character whose dimensional analysis yields a fractal dimension of 1.63 ± 0.07. The different models for island growth are discussed in the light of these results. 相似文献
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Herranz G Ranchal R Bibes M Jaffrès H Jacquet E Maurice JL Bouzehouane K Wyczisk F Tafra E Basletic M Hamzic A Colliex C Contour JP Barthélémy A Fert A 《Physical review letters》2006,96(2):027207
We report on tunneling magnetoresistance (TMR) experiments that demonstrate the existence of a significant spin polarization in Co-doped (La, Sr)TiO(3-delta) (Co-LSTO), a ferromagnetic diluted magnetic oxide system (DMOS) with high Curie temperature. These TMR experiments have been performed on magnetic tunnel junctions associating Co-LSTO and Co electrodes. Extensive structural analysis of Co-LSTO combining high-resolution transmission electron microscopy and Auger electron spectroscopy excluded the presence of Co clusters in the Co-LSTO layer and thus, the measured ferromagnetism and high spin polarization are intrinsic properties of this DMOS. Our results argue for the DMOS approach with complex oxide materials in spintronics. 相似文献
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