Abstract
Compositionally modulated TbFe and TbFeCo amorphous films were prepared on glass substrates by means of the bias modulated sputtering method. The modulated structure was confirmed for the modulation length larger than 14Å by X-ray small angle diffraction. Also, sharp layer-boundaries were clearly observed by the cross-sectional TEM method. The magnetic perpendicular anisotropy energy Ku increases with decreasing modulation length Λ, because of the interface anisotropy Ks which arises from the anisotropic ordering of Tb-Fe atom pairs or the internal stress at the layer-boundaries. Dy-Fe multilayered films prepared by a vacuum evaporation technique were also investigated. As the periodic length Λ decreases, both the saturation magnetization Ms and the Kerr rotation angle θK decrease steeply at Λ nearly euals 40Å, because of the change in Fecrystal structure from bcc to fcc or amorphous. The perpendicular anisotropy Ku increases proportionally to 1/Λ with the interface anisotropy Ks=0.8 erg/cm2 and Ks=1.24 erg/cm2 for R. T. and 80 K, respectively.
