Transistors, the building blocks of modern electronics, are typically made of silicon. Because it’s a semiconductor, this material can control the flow of electricity in a circuit. But silicon has fundamental physical limits that restrict how compact and energy-efficient a transistor can be.

MIT researchers have now replaced silicon with a magnetic semiconductor, creating a magnetic transistor that could enable smaller, faster, and more energy-efficient circuits. The material’s magnetism strongly influences its electronic behavior, leading to more efficient control of the flow of electricity. 

The team used a novel magnetic material and an optimization process that reduces the material’s defects, which boosts the transistor’s performance.

The material’s unique magnetic properties also allow for transistors with built-in memory, which would simplify circuit design and unlock new applications for high-performance electronics.

“People have known about magnets for thousands of years, but there are very limited ways to incorporate magnetism into electronics. We have shown a new way to efficiently utilize magnetism that opens up a lot of possibilities for future applications and research,” says Chung-Tao Chou, an MIT graduate student in the departments of Electrical Engineering and Computer Science (EECS) and Physics, and co-lead author of a paper on this advance.

Chou is joined on the paper by co-lead author Eugene Park, a graduate student in the Department of Materials Science and Engineering (DMSE); Julian Klein, a DMSE research scientist; Josep Ingla-Aynes, a postdoc in the MIT Plasma Science and Fusion Center; Jagadeesh S. Moodera, a senior research scientist in the Department of Physics; and senior authors Frances Ross, TDK Professor in DMSE; and Luqiao Liu, an associate professor in EECS, and a member of the Research Laboratory of Electronics; as well as others at the University of Chemistry and Technology in Prague. The paper appears today in Physical Review Letters.

Overcoming the limits

In an electronic device, silicon semiconductor transistors act like tiny light switches that turn a circuit on and off, or amplify weak signals in a communication system. They do this using a small input voltage.

But a fundamental physical limit of silicon semiconductors prevents a transistor from operating below a certain voltage, which hinders its energy efficiency.

To make more efficient electronics, researchers have spent decades working toward magnetic transistors that utilize electron spin to control the flow of electricity. Electron spin is a fundamental property that enables electrons to behave like tiny magnets.

So far, scientists have mostly been limited to using certain magnetic materials. These lack the favorable electronic properties of semiconductors, constraining device performance.

“In this work, we combine magnetism and semiconductor physics to realize useful spintronic devices,” Liu says.

The researchers replace the silicon in the surface layer of a transistor with chromium sulfur bromide, a two-dimensional material that acts as a magnetic semiconductor.

Due to the material’s structure, researchers can switch between two magnetic states very cleanly. This makes it ideal for use in a transistor that smoothly switches between “on” and “off.”

“One of the biggest challenges we faced was finding the right material. We tried many other materials that didn’t work,” Chou says.

They discovered that changing these magnetic states modifies the material’s electronic properties, enabling low-energy operation. And unlike many other 2D materials, chromium sulfur bromide remains stable in air.

To make a transistor, the researchers pattern electrodes onto a silicon substrate, then carefully align and transfer the 2D material on top. They use tape to pick up a tiny piece of material, only a few tens of nanometers thick, and place it onto the substrate.

“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,” Chou says.

Leveraging magnetism

This lack of contamination enables their device to outperform existing magnetic transistors. Most others can only create a weak magnetic effect, changing the flow of current by a few percent or less. Their new transistor can switch or amplify the electric current by a factor of 10.

They use an external magnetic field to change the magnetic state of the material, switching the transistor using significantly less energy than would usually be required.

The material also allows them to control the magnetic states with electric current. This is important because engineers cannot apply magnetic fields to individual transistors in an electronic device. They need to control each one electrically.

The material’s magnetic properties could also enable transistors with built-in memory, simplifying the design of logic or memory circuits.

A typical memory device has a magnetic cell to store information and a transistor to read it out. Their method can combine both into one magnetic transistor.

“Now, not only are transistors turning on and off, they are also remembering information. 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,” Liu says.

Building on this demonstration, the researchers plan to further study the use of electrical current to control the device. They are also working to make their method scalable so they can fabricate arrays of transistors.

This research was supported, in part, by the Semiconductor Research Corporation, the U.S. Defense Advanced Research Projects Agency (DARPA), the U.S. National Science Foundation (NSF), the U.S. Department of Energy, the U.S. Army Research Office, and the Czech Ministry of Education, Youth, and Sports. The work was partially carried out at the MIT.nano facilities.

Microsoft gives the FBI the ability to decrypt BitLocker in response to court orders: about twenty times per year.

It’s possible for users to store those keys on a device they own, but Microsoft also recommends BitLocker users store their keys on its servers for convenience. While that means someone can access their data if they forget their password, or if repeated failed attempts to login lock the device, it also makes them vulnerable to law enforcement subpoenas and warrants.

The administration has preserved a $9.7 billion Biden-era initiative to bring renewable energy to rural areas.

The audacious plan, which would tap solar energy, collides with President Donald Trump’s efforts to expand fossil fuels to power AI.

Climate hawks and conservatives will clash as highway bill negotiations rev up in the coming weeks.

Congress is weighing several proposals that would add levies to the purchase or ownership of electric vehicles.

A federal judge sided with Sunrise Wind on Monday in its bid to lift the administration’s freeze on construction of the project.

The Sunrise Movement is organizing late-night protests outside hotels housing ICE agents.

A total of nine firms plan to join the voluntary trial to purchase sustainable aviation fuel through the Singapore Sustainable Aviation Fuel Co. being established.

The plan targets power, steel, cement, refineries and chemicals over the next five years, India’s finance minister said.

The crisis has reignited anger toward President Javier Milei, whose harsh austerity drive has slashed spending on programs and agencies that not only work to combat fires but also protect parks.

Italy’s civil protection agency said two landslides hit the town of Niscemi after torrential rain, impacting the local road network, damaging buildings and disrupting essential services.

Nature Climate Change, Published online: 03 February 2026; doi:10.1038/s41558-025-02553-1

Ocean salinity could change as the climate warms. Here the authors show that the South Indian Ocean has freshened most of the Southern Hemisphere oceans and highlight the mechanisms behind this freshening, as well as the implications for Indian Ocean stratification and structure.

The way the brain develops can shape us throughout our lives, so neuroscientists are intensely curious about how it happens. A new study by researchers in The Picower Institute for Learning and Memory at MIT that focused on visual cortex development in mice reveals that an important class of neurons follows a set of rules that, while surprising, might just create the right conditions for circuit optimization.

During early brain development, multiple types of neurons emerge in the visual cortex (where the brain processes vision). Many are “excitatory,” driving the activity of brain circuits, and others are “inhibitory,” meaning they control that activity. Just like a car needs not only an engine and a gas pedal, but also a steering wheel and brakes, a healthy balance between excitation and inhibition is required for proper brain function. During a “critical period” of development in the visual cortex, soon after the eyes first open, excitatory and inhibitory neurons forge and edit millions of connections, or synapses, to adapt nascent circuits to the incoming flood of visual experience. Over many days, in other words, the brain optimizes its attunement to the world.

In the new study in The Journal of Neuroscience, a team led by MIT research scientist Josiah Boivin and Professor Elly Nedivi visually tracked somatostatin (SST)-expressing inhibitory neurons forging synapses with excitatory cells along their sprawling dendrite branches, illustrating the action before, during, and after the critical period with unprecedented resolution. Several of the rules the SST cells appeared to follow were unexpected — for instance, unlike other cell types, their activity did not depend on visual input — but now that the scientists know these neurons’ unique trajectory, they have a new idea about how it may enable sensory activity to influence development: SST cells might help usher in the critical period by establishing the baseline level of inhibition needed to ensure that only certain types of sensory input will trigger circuit refinement.

“Why would you need part of the circuit that’s not really sensitive to experience? It could be that it’s setting things up for the experience-dependent components to do their thing,” says Nedivi, the William R. and Linda R. Young Professor in the Picower Institute and MIT’s departments of Biology and Brain and Cognitive Sciences.

Boivin adds: “We don’t yet know whether SST neurons play a causal role in the opening of the critical period, but they are certainly in the right place at the right time to sculpt cortical circuitry at a crucial developmental stage.”

A unique trajectory

To visualize SST-to-excitatory synapse development, Nedivi and Boivin’s team used a genetic technique that pairs expression of synaptic proteins with fluorescent molecules to resolve the appearance of the “boutons” SST cells use to reach out to excitatory neurons. They then performed a technique called eMAP, developed by Kwanghun Chung’s lab in the Picower Institute, that expands and clears brain tissue to increase magnification, allowing super-resolution visualization of the actual synapses those boutons ultimately formed with excitatory cells along their dendrites. Co-author and postdoc Bettina Schmerl helped lead the eMAP work.

These new techniques revealed that SST bouton appearance and then synapse formation surged dramatically when the eyes opened, and then as the critical period got underway. But while excitatory neurons during this time frame are still maturing, first in the deepest layers of the cortex and later in its more superficial layers, the SST boutons blanketed all layers simultaneously, meaning that, perhaps counterintuitively, they sought to establish their inhibitory influence regardless of the maturation stage of their intended partners.

Many studies have shown that eye opening and the onset of visual experience sets in motion the development and elaboration of excitatory cells and another major inhibitory neuron type (parvalbumin-expressing cells). Raising mice in the dark for different lengths of time, for instance, can distinctly alter what happens with these cells. Not so for the SST neurons. The new study showed that varying lengths of darkness had no effect on the trajectory of SST bouton and synapse appearance; it remained invariant, suggesting it is preordained by a genetic program or an age-related molecular signal, rather than experience.

Moreover, after the initial frenzy of synapse formation during development, many synapses are then edited, or pruned away, so that only the ones needed for appropriate sensory responses endure. Again, the SST boutons and synapses proved to be exempt from these redactions. Although the pace of new SST synapse formation slowed at the peak of the critical period, the net number of synapses never declined, and even continued increasing into adulthood.

“While a lot of people think that the only difference between inhibition and excitation is their valence, this demonstrates that inhibition works by a totally different set of rules,” Nedivi says.

In all, while other cell types were tailoring their synaptic populations to incoming experience, the SST neurons appeared to provide an early but steady inhibitory influence across all layers of the cortex. After excitatory synapses have been pruned back by the time of adulthood, the continued upward trickle of SST inhibition may contribute to the increase in the inhibition to excitation ratio that still allows the adult brain to learn, but not as dramatically or as flexibly as during early childhood.

A platform for future studies

In addition to shedding light on typical brain development, Nedivi says, the study’s techniques can enable side-by-side comparisons in mouse models of neurodevelopmental disorders such as autism or epilepsy, where aberrations of excitation and inhibition balance are implicated.

Future studies using the techniques can also look at how different cell types connect with each other in brain regions other than the visual cortex, she adds.

Boivin, who will soon open his own lab as a faculty member at Amherst College, says he is eager to apply the work in new ways.

“I’m excited to continue investigating inhibitory synapse formation on genetically defined cell types in my future lab,” Boivin says. “I plan to focus on the development of limbic brain regions that regulate behaviors relevant to adolescent mental health.”

In addition to Nedivi, Boivin and Schmerl, the paper’s other authors are Kendyll Martin and Chia-Fang Lee.

Funding for the study came from the National Institutes of Health, the Office of Naval Research, and the Freedom Together Foundation.

There’s a new report about two AI coding assistants, used by 1.5 million developers, that are surreptitiously sending a copy of everything they ingest to China.

Maybe avoid using them.

Secretary Chris Wright handpicked five climate contrarians to write about global warming. Department experts pushed back on the findings.

The state is the first to display damage history and future risk. An ad blitz aims to increase awareness and promote flood insurance.

The state's largest utility opposes the Republican proposal, which echoes bills passed in other states.

Critics warn it could spur automakers to build bigger and more dangerous vehicles.

There’s clear interest from Democrats to take some steps to address potential demand for data centers in New York but no clear consensus.