2001/07/02 by Florian Meier, Daniel Loss · 1 citation
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Electron Spin Resonance Studies #Magnetic properties of thin films #Magnetism in coordination complexes #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.64.224411
published as Phys. Rev. B 64, 224411 (2001) · 15 pages, 5 figures
arxiv created 2001/07/02 · openalex publication_date 2001/11/20 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to create an excess spin. Using a coherent-state spin path integral formalism, we derive an effective action for the system in the presence of a magnetic field. We calculate the functional dependence of the magnetization and tunnel splitting on the magnetic field and show that the parameters of the spin Hamiltonian can be inferred from the magnetization curve. We study the spin dynamics in these systems and show that quantum tunneling of the N'eel vector also results in tunneling of the total magnetization. Hence, the spin correlation function shows a signature of N'eel vector tunneling, and electron spin resonance (ESR) techniques or ac susceptibility measurements can be used to measure both the tunneling and the decoherence rate. We compare our results with exact diagonalization studies on small ring systems. Our results can be easily generalized to a wide class of nanomagnets, such as ferritin.