Neutron spectroscopy and magnetic relaxation of the Mn$_6$ nanomagnets

TL;DR

This study uses neutron scattering to analyze the magnetic properties of Mn6 nanomagnets, revealing complex energy spectra and relaxation processes influenced by excited spin states, which differ from simpler giant-spin models.

Contribution

It provides a detailed microscopic Hamiltonian for Mn6 nanomagnets and highlights the impact of excited spin multiplets on their magnetic relaxation behaviors.

Findings

Presence of overlapping excited spin multiplets with the ground state

Energy barrier height is affected by low-lying excited states

Resonant tunnelling processes are significantly influenced by these excitations

Abstract

Inelastic neutron scattering has been used to determine the microscopic Hamiltonian describing two high-spin variants of the high-anisotropy Mn$_6$ nanomagnet. The energy spectrum of both systems is characterized by the presence of several excited total-spin multiplets partially overlapping the S=12 ground multiplet. This implies that the relaxation processes of these molecules are different from those occurring in prototype giant-spin nanomagnets. In particular, we show that both the height of the energy barrier and resonant tunnelling processes are greatly influenced by low-lying excited total-spin multiplets.