Shape determines properties
Jülich, 10 May 2017 – A team of researchers from Jülich and Potsdam has for the first time produced monodisperse mesocrystals, which behave magnetically like single crystals, from a magnetic material known as magnetite. "Monodisperse" means that the particles created are all of the same size; in this example, 40 nanometres. Mesocrystals are crystals made up of nanocrystals, in this case of superparamagnetic magnetite. The particles can now be used as a model system to improve the fields of application of magnetite particles. Magnetite is a component of iron ore and is currently used for instance as a medical contrast agent.
The researchers took advantage of the fact that mesocrystals often possess other properties than those of the crystals of which they are made. Nature itself offers us an example: the spines of a sea urchin, instead of consisting of fragile calcite crystals, are made of much more shock-resistant mesocrystals. Ultra-high resolution electron microscopy and holography made it possible for the scientists to clarify the connection between structure and magnetic properties despite the tiny dimensions of the particles.
An electron hologram makes visible the magnetic fields of six mesocrystals, each of which is made up of much smaller magnetite nanocrystals.
Copyright: Forschungszentrum Jülich, licensed under a Creative Commons Attribution 4.0 International License.
Original publication: Single crystalline superstructured stable single domain magnetite nanoparticles
V Reichel, A Kovács, M Kumari, É Bereczk-Tompa, E Schneck, P Diehle, M Pósfai, A M Hirt, M Duchamp, R E Dunin-Borkowski and D Faivre
Scientific Reports 7, Article number: 45484, Published: 30 March 2017, DOI:10.1038/srep45484
Contact:
Dr. András Kovács, Ernst Ruska-Centrum (ER-C-1)
Tel.: +49 2461 61-9276
Email: a.kovacs@fz-juelich.de
Press contact:
Angela Wenzik
Science journalist, Forschungszentrum Jülich
Tel.: +49 2461 61-6048
Email: a.wenzik@fz-juelich.de