Direct observation of surface and interface magnetism with the probing depth-dependent X-ray magnetic circular dichroism technique

Surface and interface magnetization of Fe/Ni/Cu(1 0 0) thin films was observed with the probing depth-dependent X-ray magnetic circular dichroism technique, in which the probing depth is controlled by changing the electron detection angle. An oscillatory behaviour of the surface magnetization dependent on the Fe thickness was directly revealed, while simple analyses indicated that the interface (bottom) Fe magnetization stays almost unchanged independent of the Fe thickness, and that the inner layers are basically nonmagnetic. These results suggest an oscillatory interlayer magnetic coupling between the surface and interface of the Fe film via the nonmagnetic inner layers. It was indicated that the observed oscillation can also be attributed to a rotatory interlayer coupling between the surface and interface. A temperature-dependent experiment indicated that the surface magnetization is reversed depending on the temperature, which might be attributed to the magnetic structural change in the inner layers