MIT Develops Magnetic Transistor with Built-In Memory

• MIT engineers create a magnetic transistor using chromium sulfur bromide, enabling low-energy switching and integrated memory functions.

Rethinking the Role of Magnetism in Electronics

MIT researchers have introduced a new type of transistor that replaces traditional silicon with a magnetic semiconductor, offering improved energy efficiency and integrated memory capabilities. The device uses chromium sulfur bromide, a two-dimensional material whose magnetic properties directly influence its electronic behavior. This approach allows the transistor to switch between states with minimal energy input, addressing long-standing limitations of silicon-based designs. Unlike many other 2D materials, chromium sulfur bromide remains stable in air, making it suitable for practical applications.

The team optimized the material to reduce defects, which enhanced its performance and reliability. By leveraging magnetism, the transistor can amplify or switch electric current more effectively than previous magnetic devices. The researchers also demonstrated that the magnetic states can be controlled electrically, a key requirement for scalable integration into electronic systems. This dual capability—switching and memory—could simplify circuit architecture and open new possibilities for compact, high-performance electronics.

Overcoming Silicon’s Physical Constraints

Traditional silicon transistors operate by controlling the flow of electricity with a small input voltage, functioning as switches or amplifiers in electronic circuits. However, silicon has a physical threshold below which it cannot operate efficiently, limiting its potential for further miniaturization and energy savings. For decades, scientists have explored magnetic transistors that use electron spin to manage current flow, but suitable materials have been scarce. Most magnetic materials lack the electronic properties needed for high-performance devices.

In this study, the MIT team combined semiconductor physics with magnetism to create a functional spintronic device. The structure of chromium sulfur bromide allows for clean transitions between magnetic states, enabling precise control over the transistor’s behavior. Researchers used a dry transfer method to place the material onto a silicon substrate, avoiding contamination that could degrade performance. This clean fabrication process contributed to the device’s ability to outperform existing magnetic transistors.

Toward Scalable, Memory-Integrated Devices

The new transistor can change current flow by a factor of ten, a significant improvement over previous designs that achieved only minor modulation. External magnetic fields were used to switch the device, but the material also responds to electric current, which is essential for practical deployment in electronics. Engineers typically require electrical control at the individual transistor level, and this material meets that need. Its magnetic properties also enable memory functionality, allowing a single device to store and process information.

Conventional memory systems separate storage and readout components, but this transistor integrates both functions. The result is a stronger signal and faster, more reliable data retrieval. Researchers plan to explore further electrical control mechanisms and develop scalable fabrication techniques for transistor arrays. Their work lays the foundation for future electronics that are smaller, faster, and more energy-efficient.