Huge Transverse Magnetization in the Field-Induced Phase of the Antiferromagnetic Molecular Wheel CsFe8

The 1H-NMR spectrum and nuclear relaxation rate 1/T_1 in the antiferromagnetic wheel CsFe8 were measured to characterize the previously observed magnetic field-induced low-temperature phase around the level crossing at 8 T. The data show that the phase is characterized by a huge staggered transverse polarization of the electronic Fe spins, and the opening of a gap, providing microscopic evidence for the interpretation of the phase as a field-induced magneto-elastic instability.