Decay of time-correlations of microscopic observables in magnetic molecules
| Autor: | Stefano Carretta, Giuseppe Amoretti, E. Liviotti, Paolo Santini |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Physics
Condensed matter physics Phonon Dynamic structure factor Condensed Matter Physics Electronic Optical and Magnetic Materials Magnetization symbols.namesake Ferromagnetism Master equation symbols Antiferromagnetism Condensed Matter::Strongly Correlated Electrons Electrical and Electronic Engineering Exponential decay Hamiltonian (quantum mechanics) |
| Zdroj: | Physica B: Condensed Matter. :109-113 |
| ISSN: | 0921-4526 |
| DOI: | 10.1016/j.physb.2005.11.028 |
| Popis: | We derive a general expression for the quasielastic part of the dynamic structure factor in the presence of a heat bath, starting from the master equation applied to the full microscopic Hamiltonian. By specializing this expression to the case of the total spin, we investigate the time autocorrelation of the molecular magnetization M for three classes of magnetic molecules (antiferromagnetic rings, grids and nanomagnets), in contact with the phonon heat bath. We find that the exponential decay of the fluctuations of M , associated with the irreversible exchange of energy with the heat bath, is characterized by a single decay time for not too high temperature and field. Such fluctuations are effectively probed by nuclear magnetic resonance (NMR), and the calculations are in very good agreement with existing experimental NMR data. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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