Ion-irradiation-induced modifications of a periodic Pt/C multilayer system containing Fe impurity have been analyzed by transmission electron microscopy (TEM). The multilayer stack with 16 Pt/C layer pairs (period 4.23 nm) was fabricated on a glass substrate. A 2 MeV Au2+ ion beam was rastered on the sample to obtain uniformly irradiated strips with fluences from 1×1014 to 1×1015ions/cm2. Ion-irradiation has been found to cause preferential migration of Fe towards Pt layers [Nucl. Instr. Methods Phys. Res. B212 (2003) 530]. Cross-sectional transmission electron microscopy (XTEM) shows considerable atomic redistribution for irradiation at the highest ion fluence (1×1015ions/cm2). Individual entities in this structure is like a cluster. Periodic multilayers have periodicity only in the direction normal to the multilayer surface. However, Fourier transform of the XTEM images of the sample irradiated at the highest-fluence shows new off-normal Fourier components of superlattice periodicities arising due to ion irradiation. With a proper understanding of this phenomenon it may be possible to fabricate three dimensional periodic structures of nanoclusters.
@article{arxiv.cond-mat/0501276,
title = {Ion-beam induced 1D to 3D periodic transformation in nanostructured multilayers},
author = {S. Bera and B. Satpati and K. Bhattacharjee and P. V. Satyam and B. N. Dev},
journal= {arXiv preprint arXiv:cond-mat/0501276},
year = {2007}
}