Quantum Spin Dynamics in Single-Molecule Magnets
摘要
This thesis contains a thorough investigation of the quantum spin dynamics in Mn12-ac and Mn6 Single-molecule magnets. In particular, we have investigated the interplay between quantum tunneling of magnetization and nuclear spin dynamics in Mn12-ac by ultra-low temperature NMR experiments. We discuss the effect of quantum tunneling on the nuclear spin-lattice relaxation, the nuclear spin diffusion, the thermalization of the nuclear spins, the isotope effect, the influence of strong perpendicular fields, and we propose a model to unify all our observations. For the isotropic Mn6 molecule, we report the observation of long-range ferromagentic ordering of the cluster spins, due to dipolar interactions only. The nuclear spin dynamics provides an interesting comparison with the case of Mn12-ac. Two large introductory chapters describe the design of our ultra-low temperature setups, and the theoretical background necessary to understand the interplay between nuclear spins and quantum tunneling, with emphasis on the Prokof'ev-Stamp theory of the "spin-bath".
引用
@article{arxiv.cond-mat/0404049,
title = {Quantum Spin Dynamics in Single-Molecule Magnets},
author = {Andrea Morello},
journal= {arXiv preprint arXiv:cond-mat/0404049},
year = {2009}
}
备注
Ph.D. Thesis, Leiden University, The Netherlands. ISBN: 90-77595-20-1. LaTex2e, 146 pages, 65 eps figures