Magnetism opens path to next-generation microchips

Materials World magazine
12 Nov 2018


Controlling magnetism in a microchip through variations in voltage could lead the way to innovations in computing and sensing devices, according to a research group from the Massachusetts Institute of Technology (MIT), USA.

Silicon microchips are rapidly approaching their fundamental physical limits, limiting their ability to both increase capabilities and reducing power consumption. Using spintronics – utilising the spin of electrons, rather than their electrical charge – can help devices retain their magnetic properties without the need for a constant power supply, but one of the biggest obstacles to overcome is in the means of easily and rapidly controlling the magnetic properties.

Previously attempts including using oxygen ions to oxidise a thin layer of magnetic material, changing its magnetic properties, although the movement of oxygen ions causes the material to swell and shrink within a few repetitions. The MIT group, led by Geoffrey Beach, Professor of Materials Science, and graduate student Aik Jun Tan, discovered using hydrogen ions, which are much smaller, produces no degradation after 2,000 cycles.

Tan said, ‘When you pump hydrogen toward the magnet, the magnetisation rotates. You can actually toggle the direction of the magnetisation by 90˚ by applying a voltage, and it is fully reversible.’ The team state the process requires very little voltage to begin, and no power at all to reverse.

Their work remains in very early stages, with Beach predicting lab-based prototypes ‘within a few years or less’.

Image: Hydrogen ions, showed as red dots, migrate through the intermediate material to change the magnetic properties of an adjacent magnetic layer, shown in green. Credit: MIT.