FMR-PNR with Non-Collinear Polarization-Magnetisation Geometry

In a previous experiment we aimed to measure the in-situ ferromagnetic resonance (FMR) with polarised neutron reflectivity (PNR) using a ferromagnetically coupled Co/Ru superlattice. The objective was to detect magnetisation dynamics and potentially spin pumping so that PNR could offer insights into the depth dependence of these effects and quantify e.g. the cone angle of the magnetisation oscillation. Understanding magnetisation dynamics is very important in many spintronics devices and applications as it determines e.g. the speed and energy cost of switching the magnetisation. The results we obtained in our first beamtime were very promising but inconclusive. Here, we will carry out the experiment in a non-collinear geometry where the neutron polarization is at an angle with respect to the sample magnetisation.