X-ray study of the structure and order in lithographic Cu₃Au nano-cuboids

¹ Max-Planck Institut für Metallforschung - D-70569 Stuttgart, Germany and Universität Stuttgart, Institut für Theoretische und Angewandte Physik D-70569 Stuttgart, Germany
² Institut für Festkörper- und Werkstofforschung - D-01069 Dresden, Germany
³ Laboratoire de Physique des Solides, Université Paris Sud 91405 Orsay, France

Received: 21 December 2001
Accepted: 6 March 2002

Abstract

We present a structural and thermodynamic study of lithographically produced Cu₃Au nano-structures on a sample which contained both an array of periodically arranged nano-cuboids with a size of nm³ and a closed thin film. It is shown that the coherence features of the X-ray beam and the periodical arrangement of the nano-structures give rise to an unusual interference pattern which is exploited as a control tool for the sample quality during the experiment. With this in hand, the L1₂-A₂ phase transformation in the nano-structures is investigated together with the behaviour of the thin film which can be compared in situ. The temperature-dependent study at this order-disorder phase transformation yields a remarkable difference in the transition temperature T_c, where T_c of the nano-cuboids is about 200 K lower than in the closed film.