Karmactive Team
MIT engineers have developed a new type of transistor that uses magnetism instead of silicon, potentially paving the way for smaller, faster, and more energy-efficient electronic devices.
Transistors are the basic building blocks of modern electronics, acting like tiny switches that control the flow of electricity in circuits. For decades, these components have been made using silicon. However, silicon has physical limits that restrict how small and energy-efficient transistors can become.
The MIT research team tackled this challenge by replacing silicon with a magnetic semiconductor called chromium sulfur bromide. This material combines the electronic advantages of semiconductors with magnetic properties that allow for better control of electrical current.
“People have known about magnets for thousands of years, but there are very limited ways to incorporate magnetism into electronics,” says Chung-Tao Chou, an MIT graduate student who co-led the research. “We have shown a new way to efficiently utilize magnetism that opens up a lot of possibilities.”
The new magnetic transistor outperforms previous attempts at similar technology. While earlier versions could only change electrical current by a few percent, the MIT device can switch or amplify current by a factor of 10. This stronger switching ability means clearer, more reliable signals.
The material also offers practical advantages that could make it useful in real-world applications. Unlike many advanced materials that degrade in air, chromium sulfur bromide remains stable when exposed to oxygen. This stability makes it easier to manufacture and work with.
The team used a careful technique to build their transistor. They patterned electrodes onto a silicon base, then used tape to precisely place an extremely thin layer of the magnetic material on top. This simple transfer method avoids using chemicals that could contaminate the surface.
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“A lot of researchers will use solvents or glue to do the transfer, but transistors require a very clean surface. We eliminate all those risks by simplifying this step,” explains Chou.
One of the most promising aspects of the new technology is that these magnetic transistors could have built-in memory. Current electronic devices typically need separate components for processing and memory storage, but the magnetic transistor could potentially do both jobs.
“Now, not only are transistors turning on and off, they are also remembering information,” says Luqiao Liu, an associate professor at MIT who supervised the research. “And because we can switch the transistor with greater magnitude, the signal is much stronger so we can read out the information faster, and in a much more reliable way.”
This dual functionality could simplify circuit design and lead to devices that use less power while performing better.
Currently, the researchers use an external magnetic field to control their device, but they’re working on methods to control it with electric current instead. This advancement would be crucial for practical applications, as engineers need to control individual transistors electrically in actual devices.
The team is also developing ways to scale up their process to create arrays of these transistors rather than single units.
The research, published in Physical Review Letters, was supported by several government agencies, including the Defense Advanced Research Projects Agency (DARPA), the National Science Foundation, the Department of Energy, and the Army Research Office.
