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Laboratory for Natural Magnetism

Holographic image of a ring consisting of several magnetite crystals
Image: P. Formanek photographed in the Triebenberglabor Dresden

Holographic image of a ring consisting of several magnetite crystals (ring in the centre of the picture). The white and black lines are magnetic field lines. The ring forms its own magnetic field with two poles (dipole). At the poles the field lines enter the ring and leave it, respectively.

Ring consisting of 13 magnetite crystals
Image: P. Formanek

The image shows a ring consisting of 13 magnetite crystals. It was taken in a transmission electron microscope (TEM). Such microscopes are suited to illustrate very small structures. A single magnetite crystal is only 0.000035 millimeter in diameter; the ring itself is only 0.000215 millimeter. If the magnetite-ring is magnetized and tilted within the TEM, its angle towards the electronic beam changes.

Hologram or holographic phase image
Image: P. Formanek

If the pictures taken from different angles are superimposed, the magnetic field of the ring within and outside the ring is revealed. The resulting photo is called a (magnetic) hologram or holographic phase image.

Image of the Earth and Planetary Magnetism group

The group investigates magnetic properties of minerals, sediments, rocks, and biomaterials, as well as Earth's paleomagnetic field and its changes over geological time-scales.

Earth- and Planetary Magnetism at ETH Zurich
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