The Role of Spin-Orbit Coupling and Anisotropy in Multi-Q Magnetic Order

Multi-Q magnetism is a form of magnetic order in which the arms of the star of magnetic propagation are interconnected, so that a two-dimensional (or indeed higher-dimensional) superstructures form. Skyrmions, vortex-like magnetic structures, are perhaps the most notable example of multi-Q order. Multi-Q order frequently gives rise to emergent phenomena such as the topological Hall effect and non-reciprocal response, and these effects may well find use in topological spintronics.
The primary objective of this experiment will be to measure and analyse the crystal field excitations in TbRu2Si2 and TbRu2Ge2 using the MARI spectrometer. With this information, we will be able to determine the form of magnetic anisotropy in both materials, which will feed into the development of model Hamiltonians so that the magnetic phase diagrams for both materials and moreover the fundamental mechanism behind the multi-Q order in both materials may be understood.