2005/08/31 by M. Evangelisti, Marco Evangelisti, Fernando Luis +6 · 2 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced NMR Techniques and Applications #Lanthanide and Transition Metal Complexes #Magnetism in coordination complexes #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.95.227206
published as Phys. Rev. Lett. 95, 227206 (2005) · Replaced with version accepted for publication in Physical Review Letters
arxiv created 2005/10/07 · openalex publication_date 2005/11/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
Time-dependent specific heat experiments on the molecular nanomagnet Fe8 and the isotopic enriched analogue 57Fe8 are presented. The inclusion of the 57Fe nuclear spins leads to a huge enhancement of the specific heat below 1 K, ascribed to a strong increase in the spin-lattice relaxation rate gamma arising from incoherent, nuclear-spin-mediated magnetic quantum tunneling (MQT) in the ground doublet. Since gamma is found comparable to the expected tunneling rate, the MQT process has to be inelastic. A model for the coupling of the tunneling spins to the lattice is presented. Under transverse field, a crossover from nuclear-spin-mediated to phonon-induced tunneling is observed.