Lattice expansion by oxygen addition to control crystallographic orientations in chemically ordered L10 FePt films

L1₀ FePt thin films attract attention for extremely high densities beyond 1 Tera bit/in² due to their large magnetocrystalline anisotropy (7-10times10⁷ ergs/cc). However, chemically ordered [001] FePt films are not easily tailored on conventional substrates. Hetero-epitaxial underlayers, post-annealed FePt multilayer films, and low kinetic deposition have been suggested to develop the [001] c-axis orientation for perpendicular media applications. In this work, oxygen was introduced to reduce the lattice mismatch with underlayer stack, aiming the [001] FePt films on commercial polycrystalline substrates.