The magnetic ground state of the elemental spin-liquid candidate beta-Mn

The aim of this proposal is to characterise the magnetic ground state of beta-Mn at mK temperatures using the WISH diffractometer. It has been claimed for many years that geometric frustration of Mn atoms on the beta-Mn hyperkagome lattice impedes the formation of a long-range ordered state at low temperatures, despite strong spin-correlations from room temperature which indicate large exchange interactions. However, and astonishingly, this claim has never been checked directly with neutron powder diffraction at mK temperatures. Recent muon measurements see some sort of dynamical cross-over and around 700 mK, but heat capacity measurements see no sign of a phase transition at low temperatures. This experiment will either confirm beta-Mn as a strongly correlated spin-liquid, or else enable the characterisation of the long-range ordered ground state if it exists.