One-dimensional spin fluctuations in a transition metal oxide

Abstract

We use inelastic neutron scattering from polycrystalline Y2BaNiO5 and Y2BaNi0.96Zn0.04O5 specimens to demonstrate that the spin fluctuations in this compound are one-dimensional. In addition they are gapped, in accord with the S=1 nature of the Ni2+ and the Haldane conjecture. The gap remains well defined and may even grow slightly in the Zn-diluted compound.