STACKS of nanomagnets could make future supercomputers run leaner. Microchips made from tiny magnets rather than conventional power-hungry transistors may enable intensive number-crunching tasks like codebreaking or image-processing using a fraction of the power.

In traditional computer chips, the bits of information, 0s and 1s, are represented by voltages across a transistor, each of which needs its own wire. But magnets can do the same job by switching their pole orientation: pointing north-south represents 1, say, and south-north is 0. Flipping poles takes less energy than running current through a wire, so they need less power to run.

Nanomagnets have already been placed on microchip surfaces in a single layer, but they need extra space to work properly. Building them in 3D is critical if they are to rival the density of transistor-based designs.

Now, a team led by Irina Eichwald at the Technical University of Munich in Germany has worked out how to grow a chip with number-crunching layers 100 nanomagnets deep.


The team made a logic gate, one of the essential building blocks of a computer, from stacked arrays of nanomagnets. Instead of wires, a handful of magnets above the chip induced magnetic fields. The magnets then flip their orientation one after the other, like dominoes, to the magnet performing the actual operation. In a test, the magnetic chip used 1/35th of the power a transistor used (Nanotechnology, doi.org/tz3).

“A huge number of computing processes can now be done simultaneously with very low power consumption as you don’t need the connecting wires transistors need. You only need to generate a magnetic field across the chip,” says Eichwald.

It has potential, says Peter Bentley at University College London. “It’s yet another technology joining the race to replace silicon.”

This article appeared in print under the headline “Magnets rival power-hungry transistors”