Magnetic interlayer coupling in Fe/h-BN/Ni(111) probed by soft X-ray magnetic circular dichroism

We investigated magnetic interlayer coupling between Fe overlayers and Ni substrate through an intermediate monolayer of hexagonal boron nitride. We performed magnetic circular dichroism experiments at L2,3 absorption edges of Fe and Ni for ultrathin-layered structure of Fe/h-BN/Ni(111) grown in-situ in ultra high vacuum environment. Antiferromagnetic coupling has been revealed with a direct evidence of opposite magnetic circular dichroism signal of Fe to Ni in the absorption spectra. The antiferromagnetic coupling energy is estimated to be in order of a hundred μeV at the interface. The comparatively small coupling energy means controllability of magnetic alignment with weak external magnetic field.