Quantum nanomagnets and nuclear spins: an overview

Abstract

This mini-review presents a simple and accessible summary on the fascinating physics of quantum nanomagnets coupled to a nuclear spin bath. These chemically synthesized systems are an ideal test ground for the theories of decoherence in mesoscopic quantum degrees of freedom, when the coupling to the environment is local and not small. We shall focus here on the most striking quantum phenomenon that occurs in such nanomagnets, namely the tunneling of their giant spin through a high anisotropy barrier. It will be shown that perturbative treatments must be discarded, and replaced by a more sophisticated formalism where the dynamics of the nanomagnet and the nuclei that couple to it are treated together from the beginning. After a critical review of the theoretical predictions and their experimental verification, we continue with a set of experimental results that challenge our present understanding, and outline the importance of filling also this last gap in the theory.

14 pages, 3 figures. Chapter in the Proceedings of the 2006 Les Houches summer school "Quantum Magnetism", ed. B. Barbara & Y. Imry, Springer (2007)

References in corpus (8)

• Quantum Coherence in an Exchange-Coupled Dimer of Single-Molecule Magnets
• Long-range ferromagnetic dipolar ordering of high-spin molecular clusters
• Nuclear spin dynamics in the quantum regime of a single-molecule magnet
• Magnetic dipolar ordering and relaxation in the high-spin molecular cluster compound Mn6
• 'Hole-digging' in ensembles of tunneling Molecular Magnets
• Giant isotope effect in the incoherent tunneling specific heat of the molecular nanomagnet Fe8
• Dynamics and thermalization of the nuclear spin bath in the single-molecule magnet Mn12-ac: test for the theory of spin tunneling
• Crossovers in spin-boson and central spin models