NMR-D study of the local spin dynamics and magnetic anisotropy in different nearly monodispersed ferrite nanoparticles

J Phys Condens Matter. 2013 Feb 13;25(6):066008. doi: 10.1088/0953-8984/25/6/066008. Epub 2013 Jan 11.


We present a systematic experimental comparison of the superparamagnetic relaxation time constants obtained by means of dynamic magnetic measurements and (1)H-NMR relaxometry, on ferrite-based nanosystems with different composition, various core sizes and dispersed in different solvents. The application of a heuristic model for the relaxivity allowed a comparison between the reversal time of magnetization as seen by NMR and the results from the AC susceptibility experiments, and an estimation of fundamental microscopic properties. A good agreement between the NMR and AC results was found when fitting the AC data to a Vogel-Fulcher law. Key parameters obtained from the model have been exploited to evaluate the impact of the contribution from magnetic anisotropy to the relaxivity curves and estimate the minimum approach distance of the bulk solvent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anisotropy
  • Ferric Compounds / chemistry*
  • Magnetic Resonance Spectroscopy*
  • Magnetics*
  • Metal Nanoparticles / chemistry*
  • Models, Chemical*
  • Spin Labels


  • Ferric Compounds
  • Spin Labels
  • ferrite