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

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 200 × 200 × 13 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 Tc, where Tc of the nano-cuboids is about 200 K lower than in the closed film.