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Peter Schurtenberger. Portrait.

Peter Schurtenberger

Professor

Peter Schurtenberger. Portrait.

Hybrid magnetic iron oxide nanoparticles with tunable field-directed self-assembly

Author

  • Vikash Malik
  • Antara Pal
  • Olivier Pravaz
  • Jerome Crassous
  • Simon Granville
  • Bernard Grobety
  • Ann M Hirt
  • Hervé Dietsch
  • Peter Schurtenberger

Summary, in English

We describe the synthesis of hybrid magnetic ellipsoidal nanoparticles that consist of a mixture of two different iron oxide phases, hematite (α-Fe2O3) and maghemite (γ-Fe2O3), and characterize their magnetic field-driven self-assembly. We demonstrate that the relative amount of the two phases can be adjusted in a continuous way by varying the reaction time during the synthesis, leading to strongly varying magnetic properties of the particles. Not only does the saturation magnetization increase dramatically as the composition of the spindles changes from hematite to maghemite, but also the direction of the induced magnetic moment changes from being parallel to the short axis of the spindle to being perpendicular to it. The magnetic dipolar interaction between the particles can be further tuned by adding a screening silica shell. Small-angle X-ray scattering (SAXS) experiments reveal that at high magnetic field, magnetic dipole–dipole interaction forces the silica coated particles to self-assemble into a distorted hexagonal crystal structure at high maghemite content. However, in the case of uncoated maghemite particles, the crystal structure is not very prominent. We interpret this as a consequence of the strong dipolar interaction between uncoated spindles that then become arrested during field-induced self-assembly into a structure riddled with defects.

Department/s

  • Physical Chemistry
  • NanoLund: Centre for Nanoscience

Publishing year

2017

Language

English

Pages

14405-14413

Publication/Series

Nanoscale

Volume

9

Issue

38

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Physical Chemistry (including Surface- and Colloid Chemistry)
  • Condensed Matter Physics (including Material Physics, Nano Physics)

Status

Published

ISBN/ISSN/Other

  • ISSN: 2040-3364