Ultrathin Co/Pt multilayered ferromagnetic film continues to be extensively studied, since it shows the contrasting reversal behaviors as well as the novel properties such as the perpendicular magnetic anisotropy (PMA) and the large Kerr rotational angle at the short wavelength.
Serial samples of Co/Pt multilayers have been prepared by dc- magnetron sputtering with varying the Co-sublayer thickness tCo and the Ar pressure. The polar Kerr hysteresis loops and the torque curves revealed that the PMA was obtained under the condition of $3 ≤ t_Co (Å) ≤ 4 and 5 ≤ P_{Ar} (mtorr) ≤ 10$.
The domain reversal dynamics of the Co/Pt multilayers has been investigated by the magnetization viscosity measurement and the direct domain observation. All samples under examination basically showed the nucleation dominant reversal behaviors. The wall-motion speed and the nucleation rate were quantitatively determined by the domain reversal model based on the time-resolved domain patterns, and it was found that the ratio of the wall-motion speed over the nucleation rate was slightly increased with increasing Ar pressure.
