Ordering in 3d-5d (CuAu) and segregation in 3d-4d (CuAg) systems

We show the differences in the stability of 3d-5d (CuAu) and 3d-4d (CuAg) alloys arise mainly due to relativistic corrections. We examine the effect of relativistic corrections to the pair energies and order-disorder transition temperatures in these alloys. The short-ranged order or segregation patterns in CuAu/CuAg alloys is also studied using the Krivoglaz-Moss-Clapp model.