Thickness-induced spin-reorientation originated from competing magnetic shape anisotropies

Engineering the surface morphology of magnetic film is one of the important methods to tune the magnetic anisotropy of ultrathin magnetic material. However, the influence of competing shape effects on magnetic anisotropy of ultrathin film is still not clearly demonstrated. Here, we investigated the magnetic anisotropy of obliquely deposited Fe films on vicinal Si(111) substrate by using in-situ and ex-situ surface magneto-optical Kerr effect (MOKE). Thickness-induced in-plane spin-reorientation transition, i.e. magnetization easy axis gradually rotates away from the step direction, was observed. MOKE measurements and micromagnetic simulation demonstrate this spin-reorientation transition process largely originated from the competition between step-induced magnetic shape anisotropy and oblique-deposition-induced magnetic shape anisotropy. Our study indicates the possibility of tuning magnetic spin order orientation by the competing magnetic shape anisotropies.