Pinpointing chiral structures with front-back polarized neutron reflectometry

In a simple extension of the typical polarized neutron reflectometry (PNR) experiment, the reflectivity from the front surface and back surface of a spring-magnet bilayer was measured. With double the number of simultaneously fitted measurements, the magnetic spiral in the buried layers was readily extracted. The technique was used to track the field evolution of the spiral in the bilayer.