Anomalous magnetic hysteresis of Gd and Fe moments in a Gd/Fe multilayer measured by hard x-ray magnetic circular dichroism

Element-specific magnetic hysteresis in a Gd/Fe multilayer has been obtained at the Gd L₃ and the Fe K edges by means of x-ray magnetic circular dichroism (XMCD) measurement with a helicity-modulation technique. Both hysteresis curves at 20 K show characteristic sharp peaks at the coercive field Hc=±50 Oe. Above Hc, the intensities of XMCD gradually decrease with increasing magnetic fields, whereas the bulk magnetization monotonously increases. These results are explained by the theoretical prediction by Camley and co-workers.