An attempt to handle the nanopatterning of materials created under ion beam mixing
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An attempt to handle the nanopatterning of materials created under ion beam mixing
D. Simeone1, G. Baldinozzi2, D. Gosset2, G. Demange2, Y. Zhang3, L. Luneville4 1 DEN/DANS/DMN/SRMA/LA2M/LRC-CARMEN, CEA Saclay, 91191 Gif-sur-Yvette, France 2 CNRS-SPMS/UMR 8580/ LRC CARMEN Ecole Centrale Paris, 92295 Châtenay- Malabry 3 Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 4 DEN/DANS/DM2S/SERMA/LLPR/LRC-CARMEN, CEA Saclay, 91191 Gif-sur-Yvette, France
ABSTRACT In the past fifty years, experimental works based on TEM or grazing incidence X ray diffraction have clearly shown that alloys and ceramics exhibit a nano pattering under irradiation [1,2,3]. Many works were devoted to study the nano patterning induced by ion beam mixing in solids [17,18,19]. Understanding the nano patterning will provide scientific bases to tailor materials with well-defined microstructures at the nanometric scale. The slowing down of impinging particles in solids leads to a complex distribution of subcascades. Each subcascade will give rise to an athermal diffusion of atoms in the medium. In this work, we focused on this point. Based on the well-known Cahn Hilliard Cook (CHC) equation, we analytically calculate the structure factor describing the nano patterning within the mean field approximation. It has shown that this analytical structure factor mimics the structure factor extracted from direct numerical simulations of the time dependent CHC equation. It appears that this structure factor exhibits a universal feature under irradiation. INTRODUCTION It is now well established that materials under irradiation exhibit unusual patterns [1,2,3,4]. Ion solid interaction is of significant interest to both academic and industrial researchers [1]. Ion implantation revolutionized the microelectronic industry offering a control over the number and depth of doping atoms in semiconductor materials [1]. Nowadays, the development of high current and high voltage implanters allows to tailor new compounds with new properties at the nanometric scale [5,6]. These unusual properties result from a steady state pattern formation induced by the slowing down of impinging particles under irradiation. From its ability to modify the local order over few nanometers, ion beam mixing appears to be a promising tool. However, elementary mechanisms responsible for this patterning are far to be clearly understood. Understanding the various mechanisms giving rise to both equilibrium and non equilibrium pattern formation in complex systems is a problem of long standing interest [7]. Two main reasons explain this lack of understanding. The slowing down of incident particles (ions, neutrons) leading to the creation of highly damaged area, termed thermal spikes or subcascades, is a stochastic process difficult to handle [8,9]. On the other hand, it remains difficult to handle the effect of a thermal spike on the microstructure of materials. From the seminal work of Martin and Bellon [10,11], it seems now well established that
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