Imaging of sub-100-nm magnetic domains in atomically stacked Fe(001)/Au(001) multilayers

In order to study sub-100-nm domains in magnetic multilayers a combination of three high-resolution imaging techniques has been applied to the same samples for the first time: magnetic force microscopy (MFM), Lorentz microscopy with a transmission electron microscope, and magnetic transmission x-ray microscopy (MTXM). The samples-atomically stacked [Fe(001)/Au(001)](n) multilayers with an approximate L1(0)-lattice-were prepared by molecular beam epitaxy (MBE) on a GaAs(001) substrate which was then locally removed by laser-induced wet etching to create a window that is transparent for 200 keV electrons and soft x-rays. Magnetization curves with perpendicular and in-plane applied field indicate a spontaneous perpendicular magnetization with an equilibrium domain pattern in small fields and reversible wall motion. About 60 nm wide domains could be observed with MFM and MTXM, respectively. Lorentz images did not show any in-plane magnetic contrast, but the domain pattern appeared when the sample was tilted. This indicates that the magnetization is indeed strictly perpendicular. (C) 2000 American Institute of Physics. [S0021-8979(00)80208-X].