Magnetic Nanotubes
The nanotubes were fabricated in the University of Cambridge Engineering department by Yasuhiko Hayashi, who grew them using a Cobalt-Palladium catalyst. This alloy remains present in the ends of the nanotubes, and is magnetic. The nanotubes you see here have a 70-100nm diameter. Characterisation of the magnetic properties was carried out by Ed Simpson and Takeshi Kasama using Electron Holography, a TEM technique which records the phase of an electron wave. The phase, being affected by any magnetic field the electron passes through, therefore records any information on the magnetic properties on the sample under investigation. From this, the magnetic induction maps you see here can be generated. The colours represent the direction and intensity of the field, and the contours, the magnetic field lines. It is an entirely quantitative technique, so as well as these images of the field, the magnetic moment, for instance, can be deduced too. (click to see full sized version)
Acknowledgments: Ed Simpson, Yasuhiko Hayashi, Takeshi Kasama and Rafal Dunin-Borkowski
Visit the University of Cambridge Department of Materials Science & Metallurgy Gallery.
I will post the others in this series over time. To see it all now, visit the Nanotechnology Now Gallery.
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