Size-dependent ultrafast magnetization dynamics in iron oxide (Fe3O4) nanocrystals. Academic Article

abstract

• Optically induced ultrafast demagnetization and its recovery in superparamagnetic colloidal iron oxide (Fe3O4) nanocrystals have been investigated via time-resolved Faraday rotation measurements. Optical excitation with near-infrared laser pulse resulted in ultrafast demagnetization in approximately 100 fs via the destruction of ferrimagnetic ordering. The degree of demagnetization increased with the excitation density, and the complete demagnetization reached at approximately 10% excitation density. The magnetization recovered on two time scales, several picoseconds and hundreds of picoseconds, which can be associated with the initial reestablishment of the ferrimagnetic ordering and the electronic relaxation back to the ground state, respectively. The amplitude of the slower recovery component increased with the size of the nanocrystals, suggesting the size-dependent ferrimagnetic ordering throughout the volume of the nanocrystal.

authors

• Son, Dong

published proceedings

• Nano Lett

author list (cited authors)

• Hsia, C., Chen, T., & Son, D. H.

citation count

• 29

complete list of authors

• Hsia, Chih-Hao||Chen, Tai-Yen||Son, Dong Hee

publication date

• February 2008

publisher

• American Chemical Society (ACS)  Publisher

published in

• Nano Letters: a journal dedicated to nanoscience and nanotechnology  Journal

keywords

• Crystallization
• Ferric Compounds
• Macromolecular Substances
• Magnetics
• Materials Testing
• Molecular Conformation
• Nanostructures
• Nanotechnology
• Particle Size
• Surface Properties

PubMed Central ID

• 18225939

Digital Object Identifier (DOI)

• 10.1021/nl072899p

start page

• 571

end page

• 576

volume

• 8

issue

• 2

URL

• http%3A%2F%2Fdx.doi.org%2F10.1021%2Fnl072899p