Kluth, P.Hoy, B.Johannessen, B.Dunn, S. G.Foran, G. J.Ridgway, M. C.2015-11-052015-11-050003-6951http://hdl.handle.net/1885/16360Co–Au core-shell nanocrystals (NCs) were formed by sequential ion implantation of Au and Co into thin SiO₂. The NCs were investigated by means of transmission electron microscopy and extended x-ray absorption fine structure spectroscopy. The latter reveals a bond length expansion in the Co core compared to monatomic Co NCs. Concomitantly, a significant contraction of the bond length and a significant reduction of the effective Au–Au coordination number were observed in the Au shells. Increased Debye-Waller factors indicate significant strain in the NCs. These experimental results verify recent theoretical predictions.P.K. and M.C.R. thank the Australian Research Council for support. P.K., B.H., B.J., and M.C.R. were supported by the Australian Synchrotron Research Program, funded by the Commonwealth of Australia via the Major National Research Facilities Program.http://www.sherpa.ac.uk/romeo/issn/0003-6951..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 5/11/15). Copyright 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.2360891Keywords: Bond length expansion; Debye-Waller factors; Nanocrystals (NC); X-ray absorption fine structures; Crystals; Ion implantation; Silica; Transmission electron microscopy; X ray photoelectron spectroscopy; Nanostructured materials2006-10-1210.1063/1.23608912015-12-08