Extracting d-orbital occupancy from magnetic Compton scattering in bilayer manganites

We consider the shape of the magnetic Compton profile (MCP), Jmag(pz), in La1.2Sr1.8Mn2O7 for momentum transfer pz along the [110] direction and the associated reciprocal form factor B(r) defined by taking the one-dimensional Fourier transform of Jmag(pz). B(r) is shown to contain a prominent dip at r≈1 Å, where the minimum value Bmin of B(r) can be related to the occupancies of the eg orbitals of dx2−y2dx2−y2 and d3z2−r2d3z2−r2 symmetry in the system. We illustrate our procedure in detail by analyzing the measured MCP at 5 K and the MCP computed within the framework of the local spin density approximation (LSDA) and comment on the differences between the measured and computed eg occupancies as a reflection of the limitations of the LSDA in treating electron correlation effects.