Rotating transverse nuclear helimagnetism in CaF₂. I. Prediction and experimental study

The authors describe the theoretical prediction of a rotating transverse helical ordering of the ¹⁹F nuclear spins in CaF₂, produced by adiabatic demagnetisation in high field, and the experimental study of its properties: resonant polarisation of the ⁴³Ca probe nuclei, the shape of the absorption signal, transverse susceptibility, spin-lattice relaxation and the variation of the ⁴³Ca NMR lineshape in the course of demagnetisation, all of which are in qualitative agreement with the theoretical predictions.