Sequential ion implantation of copper and cobalt in silica glass: A study by synchrotron radiation techniques E. Cattaruzza a , F. D’Acapito b , C. de Julian Fernandez c , A. de Lorenzi a , F. Gonella a, * , G. Mattei c , C. Maurizio c , P. Mazzoldi c , S. Padovani c , B.F. Scremin a , F. Zontone d a INFM, Department of Physical Chemistry, University of Venice, Dorsoduro 2137, I-30123 Venezia, Italy b INFM, GILDA, European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France c INFM, Department of Physics, University of Padua, via Marzolo 8, I-35131 Padova, Italy d Troika Beamline, European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France Abstract Copper–cobalt nanostructures are expected to exhibit peculiar magnetic and optical properties that make them interesting for several application fields. In particular, nanoclusters of these metals can be formed upon ion implan- tation in dielectric matrices. In this work, Co þ and Cu þ ions were sequentially implanted into fused silica. Samples were analyzed by different synchrotron radiation-based techniques, namely, extended X-ray absorption fine structure spec- troscopy and grazing incidence X-ray diffraction. The obtained cluster structure, and so its magnetic features, are observed to depend on the sequential implantation order. Ó 2002 Published by Elsevier Science B.V. Keywords: Metal nanoclusters; Ion implantation; Composite glasses 1. Introduction Ion implantation is a useful method to synthe- size composite materials for technological ap- plication. In particular, composites formed by implanting transition metals into dielectric matri- ces are particularly interesting since they exhibit peculiar optical and magnetic properties [1]. Magnetic materials in the nanometer size range exhibit new magnetic properties due to the modi- fication of the physical properties at that size order and to the surface effects. In particular, nanoclus- ters dispersed in dielectric matrices present en- hanced magnetic moment, enhanced coercivity, shift of the hysteresis loop and large magneto- transport properties. Moreover, in this particle size range, the composite material offers new tech- nological possibilities in the field of magnetic recording media for high-density information storage. The possibility to synthesize alloy based composites permits to tailor the magnetic proper- ties of these nanostructured materials. Sequential implantation of different species in the glass matrix aims at forming possible alloys with peculiar fea- tures [2]. In this work, preliminary results are re- ported on experiments in which subsequent ion irradiations with Cu þ and Co þ in silica at different Nuclear Instruments and Methods in Physics Research B 191 (2002) 406–410 www.elsevier.com/locate/nimb * Corresponding author. Tel.: +39-41-2578-595/610; fax: +39-41-2578-594. E-mail address: gonella@unive.it (F. Gonella). 0168-583X/02/$ - see front matter Ó 2002 Published by Elsevier Science B.V. PII:S0168-583X(02)00552-9