Chapter 1 - Magnetic chirality probed by polarized neutrons and neutron spin echo spectroscopy

Abstract

We discuss the interaction between a polarized neutron beam and chiral magnetism with emphasis on magnetic chirality. Without any loss of generality, we adopt a simple approach to formalism that pinpoints to the salient features of chiral magnetic scattering and can be easily used to plan and interpret experiments. We also discuss the unique information that can be derived on the topology of chiral magnetic correlations and consider the example of the skyrmion hosting system MnSi. This is one of the most simple realisations of chiral magnetism and at the same time a system, where the interaction between magnetic chirality and a polarized neutron beam is most clearly noticeable. In a next step we address the interplay between chiral magnetism and paramagnetic Neutron Spin Echo spectroscopy and then focus on the ferromagnetic Spin Echo method, which has not been discussed in the literature so far. Finally, we discuss the implications of the vector nature of the (dipole) interaction between a neutron beam polarization and a magnetic sample for the quantum mechanical description of Larmor precession-based methods.