摘要
Ni and Fe L 3,2 -edge x-ray magnetic circular dichroism (XMCD) and Ru L 3 edge x-ray absorption spectroscopy (XAS) measurements have been performed for Py/Ru(t Ru )/Py (Py = Ni 80 Fe 20 ) trilayers with t Ru = 15, 20, 25, and 30 Å. The XMCD asymmetry ratios in the Ni and Fe L 3 -edge spectra show a dip at t RU = 20 Å. At this particular thickness, the magneto-optical Kerr effect hysteresis loop measurements show that the Py-Py magnetic coupling is ferromagnetic, which differs from the antiferromagnetic couplings for other Ru spacer layer thickness. The Ru L 3 -edge XAS results show that the intensity of the white-line feature decreases rapidly as a quadratic function of t RU within the range between 15 and 30 Å.