Spin-Wave Description of Nuclear Spin-Lattice Relaxation in Mn_{12}O_{12} Acetate

TL;DR

This paper develops a modified spin-wave theory to explain nuclear spin-lattice relaxation in Mn12 acetate, successfully interpreting experimental NMR data and supporting evidence for spin delocalization across the molecule.

Contribution

It introduces a microscopic approach that improves upon previous models by accurately describing relaxation rates and spin distribution in Mn12 acetate.

Findings

The model fits temperature and field dependence of 1/T_1 for ^{55}Mn.

Supports spin delocalization over the entire molecule.

Provides a microscopic understanding of nuclear relaxation mechanisms.

Abstract

In response to recent nuclear-magnetic-resonance (NMR) measurements on the molecular cluster Mn_{12}O_{12} acetate, we study the nuclear spin-lattice relaxation rate 1/T_1 developing a modified spin-wave theory. Our microscopic new approach, which is distinct from previous macroscopic treatments of the cluster as a rigid spin of S=10, not only excellently interprets the observed temperature and applied-field dependences of 1/T_1 for ^{55}Mn nuclei but also strongly supports the ^{13}C NMR evidence for spin delocalization over the entire molecule.