Speaker: Giacomo Ghiringhelli (CNR/SPIN and Dipartimento di Fisica, Politecnico di Milano, Italy Visiting scholar at SIMES-Department of physics, Stanford University)
Program Description
When working at the L2,3 absorption edges of 3d transition metals (3dTM), resonant inelastic x-ray scattering (RIXS) provides an element and site selective access to electronic excitations (e.g. crystal field and charge transfer) and spin related excitations (e.g. magnons), in a very powerful and direct way. The large absorption cross sections allow working on thin films and very small samples too, which is not the case for neutron scattering. The sizable momentum carried by the photons in the 450-950 eV energy range allows us to explore a large fraction of the Brillouin zone in the k-space, as opposed to optical Raman. The recent experimental and theoretical advances have made possible new classes of RIXS experiments.
Using the AXES (SAXES) spectrometers at the ID08 (ADRESS) beam line of the ESRF (Swiss Light Source, SLS) we have measured the magnetic and dd excitations in NiO, layered cuprates (insulating and superconducting), LaMnO3, YTiO3, FeTe, and other 3dTM compounds. I will present some examples of dispersing and non-dispersing magnetic excitations, and some studies based on the detection of dd (crystal field) excitations.
In all cases high energy resolution and optimized photon flux is a prerequisite for meaningful measurements. This motivates the new RIXS projects under realization at various x-rays sources, not only at synchrotrons (ESRF, NSLS II, Diamond, MAX IV, NSRRC Taiwan) but also at X-FELs (LCLS, European XFEL). What could we do with RIXS in the future?
