Microstructure of L10 FePt thin films with anisotropic interfacial energy coefficients and anisotropic atomic mobilities

The microstructure evolutions of FePt-X (segregant) thin films were studied by employing a three-dimensional phase field model. Simulated 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 film thickness, anisotropic interfacial energy coefficients, and anisotropic atomic mobility. Small in-plane anisotropic interfacial energy coefficients or out-of-plane anisotropic mobility of atom diffusion are beneficial to induce columnar shape FePt grains, using any one of parameters of which can make the FePt grains keep columnar shape when FePt-X thin films thickness is 10 nm. Using segregant with both proper in-plane anisotropic interfacial energy coefficients and out-of-plane anisotropic mobility can make the FePt grains keep columnar shape when the FePt-X thin films thickness reaches to at least 15 nm.