Asymmetric domain wall propagation caused by interfacial Dzyaloshinskii-Moriya interaction in exchange biased Au/Co/NiO layered system

Dzyaloshinskii-Moriya interaction (DMI) is a well-known phenomenon in ferromagnetic/heavy metal or ferromagnetic/nonmagnetic oxide thin layered films. Here, we show that DMI is also found in exchange biased ferromagnetic/antiferromagnetic oxide layer systems and that it is independent of the macroscopic direction of the interlayer exchange bias coupling. Using the relation between thickness of the ferromagnetic layer and asymmetric domain wall propagation at external magnetic fields applied in plane and perpendicular to a sample plane of a Au/Co/NiO layered system, the strength of interfacial Dzyaloshinskii-Moriya interaction was determined. Based on this relation, we found that observed clockwise chirality is related to strong negative Dzyaloshinskii-Moriya interaction, which is independent of the direction of the interlayer exchange bias coupling. We also demonstrate that in the Au/Co/NiO system, domain motion can be controlled precisely by alternating magnetic fields. This concept can be attractive for many applications based on field-induced domain and domain wall motion, particularly in systems where exchange bias is required.