Magnetic excitations in soft X-ray RIXS: Recent developments

Resonant inelastic X-ray scattering (RIXS) has rapidly become a mature spectroscopic technique. In particular, taking advantage of an improved energy resolution, a series of experiments performed over the past 5 years have established soft X-ray RIXS as a sensitive, quantitative tool to investigate magnetic excitations in solids, complementary to more traditional probes such as neutron scattering. Most of the work has targeted cuprate systems, and the focus has progressively shifted from the antiferromagnetic insulating parent compounds to the superconducting part of the phase diagram. Here we review the most recent results, and the outstanding questions they raise.