  Implanted 3.25 keV Ar+ ions have been used to modify the in-plane bulk
anisotropy in thin films of epitaxially grown Laves phase YFe2. The magneto
optical Kerr effect, vibrating sample magnetometry and computational modeling
have been used to show that the dominant source of anisotropy changes from
magnetoelastic in as-grown samples to magnetocrystalline in ion implanted
samples. This change occurs at a critical fluence of order 1017 Ar+ ions cm-2.
The change in source of the anisotropy is attributed to a relaxation of the
strain inherent in the epitaxially grown thin-films. Atomic force microscopy
shows that the samples' topography remains unchanged after ion implantation.
The ability to control the dominant source of magnetic anisotropy without
affecting the sample surface could have important consequences in the
fabrication of patterned media for high use in density magnetic data storage
devices.
