The design of Atom probe tomography (APT) at Oxford and Rouen universities for 25 years ago has been an outstanding breakthrough in the microscopy world. APT is the only analytical microscope able to provide 3D images of a material at the atomic scale [1]. Because of its ultimate spatial resolution (0.1 nm in depth, a few tenths of a nm at the sample surface), combined with its quantitativity of composition measurements, APT has played a major role in the investigation of the early stages of phase separation in solids. APT has also been the first instrument to show Cottrell atmospheres (tiny clouds of impurity atoms around dislocations in crystals) at the atomic-scale in the three dimensions of space [2]. A new breakthrough has been achieved ten years ago with the implementation of ultrafast pulsed laser (duration < 1ps) to atom probe tomography [3]. This new generation of laser-enhanced atom probe tomograph, designed in our lab and at Madison, USA, has opened the instrument to semi-conductors and oxides that are key materials in micro-electronics and nanosciences [4,5]. Correlative approaches combining TEM with APT has been shown to be crucial for more accurate APT reconstructions of microelectronics devices [6].
A key force of APT is that 3D reconstructions can be confronted at the same scale to kinetic Monte-Carlo simulations conducted on rigid lattice. This dual approach has been recently applied to phase separation in self-organised GeMn magnetic thin films [5]. In this talk, APT results will be confronted to simulations but also to analytical models dealing with precipitation kinetics (non-classical nucleation [7], coarsening in ternary systems, influence of precipitate size on their composition [8]). A recently developed analytical model dealing with nucleation, growth and coarsening in ternary systems including diffusion coupling between chemical species has revealed that the kinetic pathway does not necessarily follow the tie lines of phase diagram in agreement with APT experiments on model nickel base superalloys [9].
[1] D. Blavette, A. Bostel, J.M. Sarrau, B. Deconihout and A. Menand, 1993, Nature 363, 432
[2] D. Blavette, E. Cadel, A. Fraczkiewicz, A. Menand, 1999, Science 17, 2317
[3] B. Gault, F. Vurpillot, A. Vella, M. Gilbert, A. Menand, D. Blavette, B., 2006, Rev. Sci. Instr. 77, 043705
[4] S. Duguay, T. Philippe, F. Cristiano, D. Blavette, Applied Physics Letter (2010) 97, 242104
[5] I. Mouton, R, Larde, E. Talbot, C. Pareige, D. Blavette, JAP 115, 053515 (2014)
[6] A. Grenier, R. Serra, G. Audoit, Jp Barnes, S. Duguay, D. Blavette, N. Rolland, F. Vurpillot, P. Morin, P. Gouraud, Applied Physics Letters 106, 213102 (2015)
[7] T. Philippe, D. Blavette, Journal Of Chemical Physics, 135, 134508 1-3 (2011)
[8] M. Bonvalet, T. Philippe, X. Sauvage, D. Blavette, Phil. Mag Vol. 94, N°26, 2956-2966 (2014)
[9] M. Bonvalet, T. Philippe, X. Sauvage, D. Blavette, Acta Materialia 100 (2015) 169-177
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