(Color online) (a) Scheme of the experimental layout developed for spectroscopy and imaging purposes. (b) Sample-mask structure cross section showing the aperture for the field-of-view (FOV) and one aperture for the reference beam.
(Color online) Effect of reference hole size on domain contrast (squares) and spatial resolution (circles) extracted from magnetic images (top) of a demagnetized [Pt/Co]8/10 nm FeMn sample. The magnetic contrast is taken from the difference between the two prominent gray scale values of the magnetic images, which correspond to Co domains with opposite out-of-plane magnetization, whereas the resolution is given by the domain wall width from line scans taken through opposite magnetic domains. The reference hole size is estimated from the scanning electron microscopy image taken from the mask-side of the structure shown in the bottom right inset.
(Color online) Absorption and XMCD spectra at the Fe- and Co- edges of a [Pt/Co] /10 nm FeMn sample recorded by the detection of the TEY signal (left) and the transmitted photon intensity (right). The sample is placed with the FeMn layer facing the incoming x-ray beam in a external field of mT. The x-axis of the graphs is split for clarity. The spectral differences in both detection modes result from different probing depth and different background contributions (see text). Note that the small dichroism signal at the Fe- edges is only seen by transmission detection.
(Color online) Normalized TEY-XMCD spectra acquired at the Mn- edges in negative (filled circles) and positive (empty squares) saturation of a [Pt/Co]/5 nm IrMn sample. The solid line is the sum of the averaged XMCD spectra. The clear nonzero sum spectra at the Mn- edge is related to the amount of uncompensated AFM moments which are fixed (pinned) during FM reversal, and its positive sign indicates that they are oriented opposite to the field cooling direction.
Co magnetic domain images of [Pt/Co]/5 nm IrMn films with n = 8 (a) and n = 4 (b) in their demagnetized states. The images are retrieved from the spatial Fourier transformation of magnetic holograms acquired at the Co- absorption edge, as described in the text. The derived domain periodicity (reference hole size) are of about 500 nm (150 nm) and 700 nm (100 nm) for the film with n = 8 and n = 4, respectively.
(Color online) Element-selective magnetic images of the [Pt/Co]/10 nm FeMn sample during magnetization reversal. Center: element-selective hysteresis loop recorded in transmission. The images retrieved from magnetic holograms (reference hole nm) recorded at Co- (top) and Fe- (bottom) absorption edges represent the magnetic domain structure of the FM layer and the uncompensated AFM moments, respectively. The magnetic contrast of the latter corresponds to an effective thicknesses as small as one monolayer thick, as derived from the spectroscopic analysis (see Fig. 3), and that mimics the FM magnetic domain structure.
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