LAUSR

Author(s): Li, Q; Yang, M; N'Diaye, AT; Dong, QY; Scholl, A; Young, AT; Gao, N; Arenholz, E; Hwang, C; Li, J; Qiu, ZQ | Abstract: © 2017 American Physical Society. Using element-resolved x-ray magnetic circular dichroism and x-ray magnetic linear dichroism measurements, we studied Ni/CoO/vicinal MgO(001) and Ni/CoO/Fe/vicinal MgO(001) systems at 350 and 78 K. Above the CoO Neel temperature, the Ni magnetization is fully in plane and parallel to the atomic steps in both systems due to step-induced magnetic anisotropy. Below the CoO Neel temperature, the CoO spins in Ni/CoO/vicinal MgO(001) are fully in plane and parallel to the atomic steps and the Ni magnetization is fully in plane and perpendicular to the atomic steps due to the 90° Ni/CoO magnetic coupling. The CoO spins in Ni/CoO/Fe/vicinal MgO(001), however, develop an out-of-plane canted spin component in addition to the in-plane component parallel to the atomic steps. Consequently, the Ni magnetization is canted towards the out-of-plane direction by an appreciable angle. Photoemission electron microscopy imaging shows a 90° interfacial magnetic coupling at both the Ni/CoO and the CoO/Fe interfaces and an absence of a direct interlayer coupling, showing that the Ni spin canting is due to its coupling to the canted CoO spin components which is caused by the underlying ferromagnetic Fe layer in Ni/CoO/Fe/vicinal MgO(001).