Magnetic Exchange Interactions in the Molecular Nanomagnet Mn$_{12}$

TL;DR

This paper uses advanced neutron scattering techniques to precisely determine the magnetic exchange interactions in the well-studied molecular nanomagnet Mn$_{12}$, overcoming previous challenges in understanding its complex magnetic couplings.

Contribution

It introduces four-dimensional inelastic neutron scattering as a novel method to accurately characterize magnetic interactions in complex molecular nanomagnets.

Findings

First unambiguous determination of exchange couplings in Mn$_{12}$

Demonstrates the effectiveness of 4D inelastic neutron scattering for magnetic studies

Provides detailed insight into spin fluctuations around the ground state

Abstract

The discovery of magnetic bistability in Mn$_{12}$ more than 20 years ago marked the birth of molecular magnetism, an extremely fertile interdisciplinary field and a powerful route to create tailored magnetic nanostructures. However, the difficulty to determine interactions in complex polycentric molecules often prevents their understanding. Mn$_{12}$ is an outstanding example of this difficulty: although it is the forefather and most studied of all molecular nanomagnets, an unambiguous determination of even the leading magnetic exchange interactions is still lacking. Here we exploit four-dimensional inelastic neutron scattering to portray how individual spins fluctuate around the magnetic ground state, thus fixing the exchange couplings of Mn$_{12}$ for the first time. Our results demonstrate the power of four-dimensional inelastic neutron scattering as an unrivaled tool to characterize magnetic clusters.