Substrate-dependent thermally driven morphological evolution of Pt$_{0.9}$Ni$_{0.1}$ thin films on sapphire and langasite

We examine the thermal evolution of 100-nm-thick Pt$_{0.9}$Ni$_{0.1}$ alloy films on sapphire and langasite substrates with a 10-nm Zr adhesion layer. Sequential vacuum annealing from room temperature to 800 $^\circ$C produces a substrate-dependent morphological pathway that is quantified by atomic