STM OBSERVED SURFACE-STRUCTURES AND MAGNETIC-PROPERTIES OF MBE-GROWN METALLIC THIN-FILMS

Rare-earth epitaxial thin films of Tb and Gd of the thicknesses betwee n 2 nm and 16 nm were deposited by means of molecular beam epitaxy met hod. The roughness of the rare-earth films measured by scanning tunnel ing microscopy was found to be in the range of 1-4.5 nm. The influence of the roughness on the dipolar anisotropy and magnetocrystalline sur face anisotropy was estimated. The magnetic measurements have shown th at the Gd layers deposited on the Y buffer layers had an easy plane an isotropy. However, for 2 nm thick Gd layer deposited on W buffer layer the perpendicular anisotropy was observed. According to the roughness analysis the possible sources of the perpendicular anisotropy in this sample is mainly the magnetoelastic anisotropy, but the presence of t he magnetocrystalline surface anisotropy also cannot be neglected.