Order-disorder transformation in Au-Cu alloys studied by extended x-ray-absorption fine structure

Abstract

We show that extended x-ray-absorption fine-structure studies can estimate the degree of shortrange order both above and below the transformation temperature of alloys displaying superlattices at low temperature. A substantial degree of short-range order was measured above the ordering temperature of 390°C for Au${\mathrm{Cu}}_3$. The local Au-Cu pair separation and its fluctuation show discontinuities at the ordering temperature. Shifts in the absorption edge were also observed at the transformation.