Growth of L10-FeNi thin films on Cu(001) single crystal substrates using oxygen and gold surfactants

We alternately deposited Ni and Fe monatomic layers on Cu(001) single crystal substrates and also performed surfactant-mediated growth. FeNi films exhibited a large uniaxial magnetic anisotropy (Ku) of over 0.1 MJ/m3 by using an oxygen or a gold surfactant, although Ku was almost zero without surfactants. Reflection high-energy electron diffraction and atomic force microscopy indicated surfactant effects of oxygen and gold. Synchrotron X-ray diffraction indicated a formation of an L10-type ordered FeNi phase having a large Ku. We have considered that the surfactants enhanced layer-by-layer growth leading to the L10-ordering by changing a diffusion scenario of Fe and Ni atoms.