Indirect Magnetic Coupling through the Nonmagnetic Au Layer in the Fe/Au/CoO Trilayer Investigated by Resonant X-ray Magnetic Scattering at the Co K Absorption Edge

Indirect magnetic coupling between a ferromagnetic Fe layer and an antiferromagnetic CoO layer through a nonmagnetic Au layer was investigated with resonant X-ray magnetic scattering (RXMS) measurement near the Co K absorption edge using circularly polarized synchrotron X-rays. The Fe/Au/CoO trilayer sample grown on the Pt(111) buffer layer was used for the RXMS measurement in an applied magnetic field of 1 kOe at room temperature, which is just above the Néel temperature of bulk CoO. It is found that only the Co atoms at the first interface atomic layer have nonzero magnetic moment and the direction of the Co moment is antiparallel to the applied magnetic field. A possible mechanism of the indirect magnetic coupling between the Fe and CoO layers through the Au layer is discussed on the basis of the result of the RXMS measurement.