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Effect of thickness ratio and interlayer exchange coupling on time-evolutional magnetization reversal process in stacked media with high coercivity was investigated by utilizing micromagnetic simulation. Regardless of the layer thickness ratio, for each stacked medium the magnetization reversal process is divided into three regions, namely the spin-flop rotation, the incoherent rotation and the coherent rotation along with increase of the interlayer exchange coupling constant Ainterlayer. In order to get the incoherent rotation region which is suitable for the recording media, it is required that the Ainterlayer is between about 1.3×10-7 and 2.2×10-7 erg/cm for the media with the layer thickness ratio of 1 : 3 and 3 : 1, and that one is between about 1.8×10-7 and 2.5×10-7 erg/cm for the media with the ratio near 1 : 1.

Influence of recording filed direction on transition noise of stacked media was investigated by using magnetic printing for recording and MFM images. Stray field fluctuation along the cross-track direction in the transition area and dispersion of the transition position of the recorded medium decreased as the applied field angle increased from the perpendicular direction. This shows that the transition noise decreases with increasing in-plane component of the recording filed. On the other hand, in the transition area domain size which corresponds to half of the period of the stray field fluctuation was fixed near 50 nm regardless of the applied field direction.

The relation between thickness and domain structure of Co80Pt20 perpendicular magnetic anisotropy films was investigated through experiments and micromagnetic simulation. The films with thickness over 10 nm exhibited clear maze domain structure, while for the films thinner than 10 nm the domain structure abruptly changed from maze domain to irregular and large domain as the thickness became thinner. The irregular domain had narrower domain wall width than maze domain.

Effect of interlayer exchange coupling on time­evolutional magnetization reversal process in ECC media with high coercivity was investigated by utilizing micromagnetic simulation. In the case of intermediate value of the interlayer exchange coupling, during the application of printing field, magnetization in the soft layer initially reverses and magnetization in the hard layer follows that of the soft layer. Furthermore, after removal of printing field, magnetization in the soft layer is reversed again according with that in the hard layer.