Fig. 6

X-ray linear dichroism (XLD) curves showing the orbital reconstruction of the interfacial Cu ions. a Schematic view of the x-ray linear dichroism experiment in total electron yield (TEY) and fluorescence yield (FY) mode. The linear polarization of the incident x-rays (at 30 degree with respect to film surface) is indicated by the red and blue arrows for the in-plane and the out-of-plane components, respectively. b–d Comparison of the XAS spectra of the NYN trilayers with y = 0.2 and y = 0.4 and a YBa₂Cu₃O₇/La_2/3Ca_1/3MnO₃ (YBCO/LCMO) superlattice. Shown are the Cu L₃ -edge spectra taken at T = 5 K and H = 0.5 T in TEY mode (top panel), which predominantly probes the top-most YBCO/manganite interface, and in FY mode (bottom panel) which is sensitive to all Cu ions. The experimental data are shown by solid symbols, the peak fitting with four Lorentzian functions as lines. The peaks (I) and (II) at 930.4 eV and 930.6 eV (that are strongest in TEY mode) are attributed to interfacial Cu ions whereas the peak (III) at 931 eV arises from the bulk-like Cu ions (that are much stronger in FY mode). The sign of the dichroism of the individual peaks is indicated by the shading