Many magnetically frustrated systems exhibit what is known as persistent spin dynamics (PSD) in $\mu$SR experiments, the origin of which has remained mysterious since their discovery in the 1990s. As the temperature is lowered, the muon-spin relaxation rate rises (as would be expected for the slowing-down of spin fluctuations) but this rate then saturates at low temperature, the...
Interacting degrees of freedom in solids underlie new emergent ground states and competing phases with potential for new functionalities. Vibrations of the atomic lattice, i.e. phonons, can couple to electrons, magnetic, or orbital degrees of freedom. In particular, electron-phonon coupling (EPC) received a lot of attention as a microscopically understood origin of superconductivity....
We discuss different concepts to realized crystal analyzer spectrometers at long pulse neutron sources. For the novel High Current Accelerator driven neutron sources, crystal arrays designed for large acceptance enable resolutions down to 10 µeV with reasonable detector count rates.
For the ESS we present a concept that might enable neV resolution by using GaAs monochromators and analyzers...
