Abstract
We fabricated a superparamagnetic ordered structure via self-assembly of a colloidal crystal from a suspension of maghemite nanoparticles and polystyrene beads. Such crystals are potential candidates for novel polarizing beam-splitters for cold neutrons, complementing the available methods of neutron polarization. Different bead sizes and nanoparticle concentrations were tested to obtain a crystal of reasonable quality. Neutron diffraction experiments in the presence of an external magnetic field were performed on the most promising sample. We demonstrate that the diffraction efficiency of such crystals can be controlled by the magnetic field. Our measurements also indicate that the Bragg diffraction regime can be reached with colloidal crystals.
| Original language | English |
|---|---|
| Pages (from-to) | 234-240 |
| Number of pages | 7 |
| Journal | Journal of Physics and Chemistry of Solids |
| Volume | 110 |
| DOIs | |
| State | Published - Nov 2017 |
| Externally published | Yes |
Funding
The authors gratefully acknowledge the financial support of Slovenian Research Agency (ARRS) in the framework of research programme Light and Matter (grant no. P1-0192), the financial support of the Centre for International Cooperation & Mobility of the Austrian Agency for International Cooperation in Education and Research (grant no. Si 13/2016 i.e. BI-AT/16-17-013), and the hospitality of the Paul Scherrer Institute and the Institut Laue Langevin. We thank H. Kabelka and P. Litschauer for providing the electromagnet. This work is partly based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland.
Keywords
- Colloidal crystals
- Neutron scattering
- Superparamagnetic nanoparticles