Simulation of FePt Columnar Microstructure Using Phase Field Model

The morphological evolutions of FePt-X (segregant) thin films were studied by employing a 3-D phase field model. Numerical simulation results show that in the absence of substrate constraint related with elastic energy, the morphology of the FePt-X thin films significantly depends on the interfacial energy, film thickness, and anisotropic atomic mobility. The large interfacial energy between FePt and X induces the FePt grains to form the nonmultilayers microstructure but it degrades the L1₀ ordering of FePt. The formation of columnar or the bilayer microstructure of FePt largely depends on a critical film thickness. Using the segregant with anisotropic atomic mobility to prepare the columnar FePt grains with high aspect ratio is advantageous in the FePt-X thin films.