  We demonstrate that combining standing-wave (SW) excitation with resonant
inelastic x-ray scattering (RIXS) can lead to depth resolution and interface
sensitivity for studying orbital and magnetic excitations in correlated oxide
heterostructures. SW-RIXS has been applied to multilayer heterostructures
consisting of a superconductor La$_{1.85}$Sr$_{0.15}$CuO$_{4}$(LSCO) and a
half-metallic ferromagnet La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO). Easily
observable SW effects on the RIXS excitations were found in these LSCO/LSMO
multilayers. In addition, we observe different depth distribution of the RIXS
excitations. The magnetic excitations are found to arise from the LSCO/LSMO
interfaces, and there is also a suggestion that one of the dd excitations comes
from the interfaces. SW-RIXS measurements of correlated-oxide and other
multilayer heterostructures should provide unique layer-resolved insights
concerning their orbital and magnetic excitations, as well as a challenge for
RIXS theory to specifically deal with interface effects.

Materials Science;Strongly Correlated Electrons;Superconductivity