Compass points towards the west

April 3, 2019 | 07:40
Compass points towards the west
Compass points towards the west
Researchers from the Paul Scherrer Institute and the Eidgenössische Technische Hochschule Zürich (both in Switzerland) have discovered a remarkable magnetic phenomenon. This phenomenon appears at the nano scale and makes it possible to construct magnets with unusual configurations. This could come in useful for computer technology and for the storage of data.

North pole and south pole

Magnets are characterised by the fact that they have both a north pole and a south pole. When normal magnets are brought near each other, opposite poles attract one another on opposite poles repel one another. This is the reason why a normal magnet can be used as a compass needle, so that we know where north and south are, and therefore also east and west.

 

When a group of cobalt atoms are pointed towards the north or south (red), cobalt atoms adjacent point towards the west or east. For this, the cobalt atoms have to be sandwiched between a layer of platinum (below) and a layer of aluminium oxide (not drawn here) (image: Paul Scherrer Institute/Zhaochu Luo).
 
However, the researchers have now discovered a very remarkable magnetic interaction that operates at the nano scale (hence the name nano-magnets). This reaction was predicted theoretically more than sixty years ago by physicists Igor Dzyaloshinskii and Toru Mariya. With this, the atomic ‘compass needles’ point not only in the north/south direction but also in the east/west direction. The direction in which they point depends on the direction of nearby atoms.

1.6 nanometres

The researchers could demonstrate this north/south and east/west orientation on a layer of cobalt atoms that is only 1.6 nanometres thick, sandwiched between a layer of platinum and a layer of aluminium oxide.
Remarkable is the the interaction takes place in one plane. This enables the development of planar magnetic networks. So it could, for example, become possible to manufacture synthetic anti-ferro magnets, on the basis of which more efficient computer memories, switches and logic gates could be built.
The research has been published in Science.

Source: ETH Zürich
 
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