MAGNETIC-ANISOTROPY IN IRON THIN-FILMS EVAPORATED UNDER ULTRA-HIGH VACUUM

Alpha-iron thin films with thickness ranging between 20 and 1500 nm have been evaporated using an electron gun under ultra-high vacuum conditions (5.10(-7) Pa). The columnar structure observed in cross-sectional TEM is related to the large surface diffusion. From Mossbauer spectra the spin orientation is deduced and found to be influenced by the column axis. Spins can be obtained perpendicularly to the film plane by rotating the substrate during the deposition. The magnetization of the samples is reduced by about 30 % and the reduction attributed to the interstitial space which increases with the incident angle. The substrate rotation also decreases Ku(//) by a factor 2 and increases Ku(perpendicular-to).