Transient spin dynamics in a single-molecule magnet

We explore the limitations and validity of semiclassically formulated spin equations of motion. Using a single-molecule magnet as a test model, we employ three qualitatively different approximation schemes. From a microscopic model, we derive a generalized spin equation of motion in which the parame...

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Bibliographic Details
Published in:Physical review. B 2017-12, Vol.96 (21), Article 214401
Main Authors: Hammar, H., Fransson, J.
Format: Article
Language:English
Subjects:
Approximation
Electron spin
Equations of motion
Mathematical models
Model testing
Parameters
Spin dynamics
Time dependence
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Summary:We explore the limitations and validity of semiclassically formulated spin equations of motion. Using a single-molecule magnet as a test model, we employ three qualitatively different approximation schemes. From a microscopic model, we derive a generalized spin equation of motion in which the parameters have a nonlocal time dependence. This dynamical equation is simplified to the Landau-Lifshitz-Gilbert equation with (i) time-dependent and (ii) time-independent parameters. We show that transient dynamics is essentially nonexisting in the latter approximation, while the former breaks down in the regime of strong coupling between the spin and the itinerant electrons.
ISSN:2469-9950
2469-9969
2469-9969
DOI:10.1103/PhysRevB.96.214401