A new material for handling magnets
A new material has been discovered by researchers at MIT, and it could have big implications for the handling of magnets. The material, chromium telluride, can naturally control the anomalous Hall effect and Berry curvature, improving efficiency and performance in magnets. This could lead to big improvements in computation, electronics, and robotics, and even flexible electronics and soft sensors that can interact with biological elements.
The anomalous Hall effect
Discovered in 1879 by British scientist named Edwin Hall, the Hall effect involves the deflection of electrical current in the presence of a magnetic field. Quantum mechanics allows for the utilisation of the asymmetrical behaviour of the Hall effect, known as the anomalous Hall effect, to control the flow of electricity – but this requires a magnetic field. Now, however, MIT has created a material that displays the anomalous Hall effect even when stretched or squeezed, opening up possibilities for flexible electronics and soft sensors.
The work, which was led by MIT associate professor of electrical engineering Kouzoh “Kou” Sato, was published in Nature Materials. It involves a material made of aluminum oxide or strontium titanate base layers with an atomic layer of chromium telluride applied on top. The interaction between the magnetic compound and the base layers gives the material its flexibility, but it is the atomic layer that exhibits the anomalous Hall effect even without a magnetic field.
“What we’ve done is create a material where the anomalous Hall effect can be seen without a magnetic field, even when the material is being strained,” Sato tells The Optical Society (OSA). “This is really unusual.”
Strain-tunable and flexible
The researchers refer to the material as “strain-tunable” because it naturally adjusts its conductance based on the strain it experiences. When the material is strained, it adjusts its electric conductance, allowing electrons to move through different pathways.
“This is a very different kind of tunability compared to something like an oxide semiconductor, which requires a lot of voltage to do its work,” says Sato. “With our material, the electron flow itself is tunable based on the strain.”
Strain-tunable materials have big implications for robotics, such as “soft sensors” that can stretch around biological elements without damaging them. They could also be used in data storage, as the stretchable material can store varying amounts of data based on how it is stretched.
There are still several factors that will influence the adoption of strain-tunable materials, such as cost and the adaptation of existing CMOS fabrication technology. However, the work is supported by various U.S. government and research bodies, and further work is expected to be done on strain-tunable materials.
“There’s a lot ahead of us,” Sato says. “But this is a really new direction.”
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