title: Quantum oscillations of the total spin in a heterometallic antiferromagnetic ring: evidence from neutron spectroscopy.
abstract: Using inelastic neutron scattering and applied fields up to 11.4 T, we have studied the spin dynamics of the Cr7Ni antiferromagnetic ring in the energy window 0.05-1.6 meV. We demonstrate that the external magnetic field induces an avoided crossing (anticrossing) between energy levels with different total-spin quantum numbers. This corresponds to quantum oscillations of the total spin of each molecule. The inelastic character of the observed excitation and the field dependence of its linewidth indicate that molecular spins oscillate coherently for a significant number of cycles. Precise signatures of the anticrossing are also found at higher energy, where measured and calculated spectra match very well.
authors.affiliation: Dipartimento di Fisica, Università di Parma, I-43100 Parma, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Carretta
authors.forename: P
authors.initials: P
authors.lastname: Santini
authors.forename: G
authors.initials: G
authors.lastname: Amoretti
authors.forename: T
authors.initials: T
authors.lastname: Guidi
authors.forename: J R D
authors.initials: JR
authors.lastname: Copley
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.forename: R
authors.initials: R
authors.lastname: Caciuffo
authors.forename: G
authors.initials: G
authors.lastname: Timco
authors.forename: R E P
authors.initials: RE
authors.lastname: Winpenny