Dependence of magnetic domain size of ultra-thin CoPt perpendicular magnetic anisotropy films on demagnetization field direction

CoPt-based thin films have been studied for magnetic devices such as magnetic recording media because of having high perpendicular magnetic anisotropy and high saturation magnetization. Although many investigations on the magnetic properties and the domain structure of CoPt-based perpendicular magnetic anisotropy films have been carried out, there has been little discussion on the relationship between the domain size and the applied field direction for ultra-thin CoPt films with thickness less than 10 nm. In this study, we clarify the dependence of the domain size on the demagnetization field direction for ultra-thin CoPt perpendicular anisotropy films.