Magnetization properties of bias modulated TbCo films with short periodic modulation

TbCo films modulated compositionally between 14.4 at% Tb and 20.1 at% Tb were prepared with the period of 3000 - 8 Å by the bias-modulated sputtering method. Two compensation temperatures of both layers in these multi-layered films approach and merge with each other with reduction of the modulation period. The magnetic hysteresis loops change tremendously depending on the period due to exchange interaction between layers. The short periodic modulation film with layer thickness of 4 Å showed the highest perpendicular anisotropy energy of 2.0 - 2.5 × 10⁶erg/cm³, and the highest Kerr effect of 0.31 deg.