Hard and Soft X-Ray Reflectivity Studies οf (NiFe//Au//Co//Au)10(NiFe//Au//Co//Au)_{10} Magnetic Multilayers

We report on hard and soft X-ray reflectivity investigations of $(Ni_{80}Fe_{20} (2.2 nm)//Au(2.3 nm)//Co(0.8 nm)//Au(2.3 nm))_{10}$ multilayers. Specular reflectivity curves were measured with Cu $K_{α}$ radiation and circularly polarized synchrotron radiation tuned to Co $L_{3}$ and Ni $L_{3}$ absorption edges. Structural properties of the multilayers were determined from the hard X-ray reflectivity curve. Comparison of reflectivity curves taken at different photon energies shows: (i) small difference in peak positions in dependence of reflectivity versus scattering vector q, (ii) different shapes of satellite Bragg peaks, (iii) different ranges of q for appearance of the Kiessig fringes. Analysis of soft X-ray reflectivity curves taken as a function of magnetic field allows to determine magnetic properties of Co and NiFe layer specifically

Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

Höink V, Schmalhorst J-M, Reiss G, et al. Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling. JOURNAL OF APPLIED PHYSICS. 2008;103(12): 123903.Artificial ferrimagnets have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment (IB) induced patterning of the exchange bias coupling of a single layer reference electrode in magnetic tunnel junctions with He ions is possible. For applications as, e.g., special types of magnetic logic, a combination of the IB induced patterning of the exchange bias coupling and the implementation of an artificial ferrimagnet as reference electrode is desirable. Here, investigations for a pinned artificial ferrimagnet with a Ru interlayer, which is frequently used in magnetic tunnel junctions, are presented. It is shown that in this kind of samples the exchange bias can be increased or rotated by IB induced magnetic patterning with 10 keV He ions without a destruction of the antiferromagnetic interlayer exchange coupling. An IrMn/Py/Co/Cu/Co stack turned out to be more sensitive to the influence of IB than the Ru based artificial ferrimagnet. (C) 2008 American Institute of Physics

Domains Stimulated Magnetostatic Coupling in NiFe/Au/Co/Au Multilayers Investigated by Complementary Methods

The magnetic structure of $Ni_{80}Fe_{20}$/Au/Co/Au multilayers characterized by easy-plane and easy-axis perpendicular to the sample plane anisotropies for NiFe and Co, respectively, is strongly modified by magnetostatic coupling resulting from stray fields of stripe domains in the Co layers. Using complementary methods it will be shown that the magnetostatic coupling increases with decreasing Au spacer thickness, with the weakening of the easy plane anisotropy of the NiFe layers and with increasing thickness of the Co layers