RIXS study of a new Cu-based spin-order in cuprate/manganite multilayers

We are studying proximity effects in multilayers of the high Tc cuprate YBa2Cu3O7(YBCO) and perovskite manganites, such as Ndx(Ca1-ySry)1-xMnO3(NCSMO), with different magnetic and charge orders. Using RIXS at the Cu L-edge for a superlattice with x=0.35 and y=0.3, we observed an unusual dispersion of the low energy excitations around 100 and 500 meV raising doubts whether they are entirely due to magnons. Our polarimetry study at ESRF, confirmed the predominant magnetic origin of these inelastic excitations. Notably, at the in-plane scattering vector of (Qx,Qy) = (0.21,0.21) rlu, we found that the spin-flip scattering even contributes to the elastic peak. Such a magnetic elastic scattering is suggestive of a new kind of Cu-based spin order(SO) that does not occur in bulk YBCO. Now we want to use the superior energy-resolution and the capability for a full polarization analysis at ID32 of ESRF to perform a detailed analysis of this new SO and related effects on the magnon dispersion.