  We show the differences in the stability of 3d-5d (NiPt and CuAu) and 3d-4d
(NiPd and CuAg) alloys arise mainly due to relativistic corrections. The
magnetic properties of disordered NiPd and NiPt alloys also differ due to these
corrections which lead to increase in the separation between s-d bands of 5d
elements in these alloys. For the magnetic case we analyze the results in terms
of splitting of majority and minority spin d-band centers of the 3d elements.
We further examine the effect of relativistic corrections to the pair energies
and order disorder transition temperatures in these alloys. The magnetic
moments and Curie temperatures have also been studied along with the short
range ordering/segregation effects in NiPt/NiPd alloys.
