Time-resolved study of surface spin effect on spin-lattice relaxation in Fe3O4 nanocrystals.

Abstract

The role of surface spins in the relaxation of magnetization in optically excited Fe(3)O(4) nanocrystals has been investigated via time-resolved Faraday rotation measurements. The time scale of the magnetization recovery following the optically induced demagnetization increased from 250 to 350 ps as the size of the nanocrystals increased from 5 to 15 nm. From analysis of the data with a simple model relating the spin-lattice relaxation rate to the average spin-orbit coupling strength of the interior and surface spins, we estimated the relative efficiency of surface in spin-lattice relaxation with respect to the interior spins. Our analysis indicates that, in Fe(3)O(4) nanocrystals passivated with oleic acid, the surface is 3 times more efficient in spin-lattice relaxation than the interior.

DOI: 10.1021/ja901484x

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Cite this paper

@article{Hsia2009TimeresolvedSO, title={Time-resolved study of surface spin effect on spin-lattice relaxation in Fe3O4 nanocrystals.}, author={Chih-Hao Hsia and Tai-Yen Chen and Dong Hee Son}, journal={Journal of the American Chemical Society}, year={2009}, volume={131 26}, pages={9146-7} }