摘要
The size-dependent chemical tunability of spin-lattice relaxation rate in magnetic nanocrystals has been investigated in size and composition-controlled colloidal superparamagnetic Co(x)Fe(3-x)O(4) nanocrystals employing pump-probe Faraday rotation measurements, With the increase of cobalt content in Co(x)Fe(3-x)O(4) nanocrystals, spin-lattice relaxation rate increased due to the increasing spin-orbit coupling strength regardless of the particle size. However, the range of the chemical tunability of spin-lattice relaxation was narrower in the smaller nanocrystals and the size dependence of spin-lattice relaxation rate became weaker with increasing cobalt content. These observations were explained in terms of weaker chemical tunability of spin-orbit coupling on the surface than in the interior of the nanocrystals using a simple model for spin-lattice relaxation rate that has both surface and interior contributions.
- 出版日期2010-6-3