Tiny magnets: a big leap for greener electronics
Researchers have unveiled a powerful new way to control ultra-thin magnetic materials which could pave the way for faster, greener technologies for computing and data storage.
Ultrathin magnets
Two-dimensional (2D) magnets are sheets of magnetic material only a few atoms thick. Because they are so thin, their magnetic behaviour can be tuned far more easily than in conventional bulk magnets. This makes them a hot candidate for spintronics devices, which use the spin of electrons instead of their charge to process and store information. Spintronic devices promise to be much faster and more energy-efficient than today’s electronics.
Ground breaking discovery
A team of researchers led by Dr Elton Santos from the School of Physics and Astronomy, showed that femtosecond laser pulses (that’s millionths of a billionth of a second) can flip the magnetisation of these materials at speeds far beyond traditional magnetic switching. Doing so with light rather than magnetic fields slashes the energy cost of each switching event and removes the need for mechanical components, allowing denser information storage with less wear and tear, significantly expanding their lifetime. The findings are featured on the front cover of Advanced Materials.
Challenges
However, this ultra-fast control comes with a challenge: heat. When such intense, ultrashort pulses hit a tiny magnetic layer, the material heats up almost instantly. If the heat can’t escape, it slows down or even disrupts the switching process. For real-world applications, controlling how heat flows away from these atom-thin layers is just as important as controlling their magnetism.
Substrate influence
To address this, the team tested three representative 2D magnets (semiconducting Cr₂Ge₂Te₆, insulating CrI₃ and metallic Fe₃GeTe₂) on a wide range of underlying substrates such as silicon dioxide, hexagonal boron nitride, graphene and other crystals. They discovered that simply choosing a different substrate changes how quickly the magnet heats and cools, and therefore how quickly it can be switched on and off by light. Substrates with higher thermal conductivity act like miniature heat sinks, letting the magnet cool down and recover its state much faster.
They also found that thinner magnetic layers reset their magnetisation more quickly than thicker ones, and that the timescales follow a clear trend linked to the substrate’s heat-handling properties. On top of the thermal effects, the researchers observed fleeting bursts of spin-polarized currents at the interface (a kind of ultrafast spin signal) that doesn’t appear in conventional thin films. These currents could be harnessed for new types of high-frequency spintronic circuits operating in the gigahertz range.
Implications
Together, these results give engineers a toolkit for designing devices where magnetism, heat and speed can be tuned on demand. In practical terms, that could mean much faster and more energy-efficient hard drives, memory chips and logic devices — all operating with light pulses instead of heavy electrical currents. It could also enable entirely new architectures for data-intensive tasks such as artificial intelligence, cloud computing and telecommunications, where today’s electronics face rising energy costs and heat bottlenecks.
By showing how to integrate ultrathin magnets with the right supporting materials, this research brings the dream of low-power, ultrafast spintronic technology a major step closer — and highlights the unique potential of 2D materials to go beyond the limits of today’s magnetic devices.