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Damped precession of the magnetization vector of superparamagnetic nanoparticles excited by femtosecond optical pulses

Andrade, L.H.F and Laraoui, A. and Vomir, M. and Muller, D. and Stoquert, J.- P. and Estournès, Claude and Beaurepaire, E. and Bigot, Jean-Yves Damped precession of the magnetization vector of superparamagnetic nanoparticles excited by femtosecond optical pulses. (2006) Physical Review Letters (PRL), vol. 97 (n° 12). pp. 127401-1. ISSN 0031-9007

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Official URL: http://dx.doi.org/10.1103/PhysRevLett.97.127401

Abstract

The ultrafast magnetization and electron dynamics of superparamagnetic cobalt nanoparticles, embedded in a dielectric matrix, have been investigated using femtosecond optical pulses. Our experimental approach allows us to bypass the superparamagnetic thermal fluctuations and to observe the trajectory of the magnetization vector which exhibits a strongly damped precession motion. The magnetization precession is damped faster in the superparamagnetic particles than in cobalt films or when the particle size decreases, suggesting that the damping is enhanced at the metal dielectric interface. Our observations question the gyroscopic nature of the magnetization pathway when superparamagnetic fluctuations take place as we discuss in the context of Brown’s model.

Item Type:Article
Additional Information:Thanks to American Physical Society editor. The definitive version is available at http://www.scitation.aip.org The original PDF of the article can be found at Physical Review Letters website : http://prl.aps.org/
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution: Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
French research institutions > Centre National de la Recherche Scientifique - CNRS
Other partners > Université Louis Pasteur-Strasbourg I - ULP (FRANCE)
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Deposited By:Celine Cabaup

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