Discrete antiferromagnetic spin-wave excitations in the giant ferric wheel Fe18

TL;DR

This study combines experimental inelastic neutron scattering with advanced numerical and analytical methods to investigate discrete antiferromagnetic spin-wave excitations in the large Fe18 molecular wheel, revealing the applicability of smaller-ring concepts.

Contribution

It provides a detailed characterization of Fe18's magnetic properties and demonstrates that spin-wave concepts from smaller rings extend to larger AFM molecular wheels.

Findings

Fe18 exhibits discrete antiferromagnetic spin-wave excitations.

The rotational-band and L&E-band concepts apply to Fe18.

The combined approach advances understanding of large magnetic molecules.

Abstract

The low-temperature elementary spin excitations in the AFM molecular wheel Fe18 were studied experimentally by inelastic neutron scattering and theoretically by modern numerical methods, such as dynamical density matrix renormalization group or quantum Monte Carlo techniques, and analytical spin-wave theory calculations. Fe18 involves eighteen spin-5/2 Fe(III) ions with a Hilbert space dimension of 10^14, constituting a physical system that is situated in a region between microscopic and macroscopic. The combined experimental and theoretical approach allowed us to characterize and discuss the magnetic properties of Fe18 in great detail. It is demonstrated that physical concepts such as the rotational-band or L&E-band concepts developed for smaller rings are still applicable. In particular, the higher-lying low-temperature elementary spin excitations in Fe18 or AFM wheels in general are of discrete antiferromagnetic spin-wave character.