Interlayer exchange coupling and interface magnetic anisotropy with crossed in-plane and perpendicular magnetic anisotropies

摘要

We investigated interlayer exchange coupling (IEC) and interface magnetic anisotropy ( K i ) between two ferromagnetic layers with crossed in-plane and perpendicular magnetic anisotropies separated by a non-magnetic spacer by using the anomalous Hall effect (AHE). The sample consisted of a Co 0.75 Fe 2.25 O 4 layer with perpendicular magnetic anisotropy and a Fe layer with in-plane anisotropy, separated by a MgO layer with variable thickness. Since Co 0.75 Fe 2.25 O 4 and MgO are insulators, the AHE signal only reflects the magnetization process of Fe. From this, we determined both IEC and K i . A strong antiferromagnetic IEC was confirmed between Co 0.75 Fe 2.25 O 4 and Fe. The strongest IEC of ?1.1 mJ/m 2 was observed for directly coupled Fe and Co 0.75 Fe 2.25 O 4 for which K i was ?1.1 mJ/m 2 .