Size and property bimodality in magnetic nanoparticle dispersions: single domain particles vs. strongly coupled nanoclusters

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift


The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic, and magnetic resonance properties. Finally, we show how the FMR spectra are influenced by dynamical effects; agglomeration of the superparamagnetic fraction leads to reversible line-broadening; rotational alignment of the suspended nanoclusters results in shape-dependent resonance shifts. The AF4 and FMR measurements described herein are fast and simple, and therefore suitable for quality control procedures in commercial production of magnetic nanoparticles.


  • E. Wetterskog
  • A. Castro
  • L. Zeng
  • S. Petronis
  • D. Heinke
  • E. Olsson
  • Lars Nilsson
  • N. Gehrke
  • P Svedlindh
Enheter & grupper
Externa organisationer
  • Chalmers University of Technology
  • SP Technical Research Institute of Sweden
  • Uppsala universitet, Historiska institutionen
  • SOLVE Research and Consultancy AB
  • nanoPET Pharma GmbH

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Nanoteknik
Sidor (från-till)4227-4235
Antal sidor9
StatusPublished - 2017 mar 28
Peer review utfördJa