Transistors are usually made from silicon, a semiconductor that can partly conduct electricity and manage its flow. However, silicon has physical limits that make transistors hard to shrink further or use less energy. Scientists at MIT have now created a magnetic transistor by replacing silicon with a magnetic semiconductor, a material whose magnetism affects how it handles electricity. This change allows better control over electric flow, leading to circuits that are more compact, quicker, and less power-hungry. The new material also adds built-in memory to transistors, which could simplify designs and open up new uses in advanced devices.
The key material is chromium sulfur bromide, a thin, two-dimensional layer that acts as a magnetic semiconductor. It can switch between magnetic states easily, helping the transistor turn on and off smoothly. Researchers faced challenges finding the right material after trying others that failed. They improved it by reducing small flaws in the structure that harm performance. To build the transistor, they pattern electrodes on a silicon base and carefully place the thin material on top using tape, avoiding dirt or chemicals that could ruin the clean surface needed.
How the transistor works
This method lets the device switch or boost electric current by a factor of 10, far better than older magnetic transistors that only change flow by a small amount. An external magnetic field flips the material's state for low-energy switching, but researchers also found ways to do this with electric current alone, which is practical for real devices since magnetic fields are hard to apply individually. The magnetism comes from electron spin, which helps control electricity without needing as much voltage as silicon. In tests, the transistor stayed stable in air, unlike many similar materials. Looking ahead, the scientists plan to explore full electrical control and ways to make groups of these transistors for larger circuits. This advance builds on known magnetic ideas but integrates them into electronics in a fresh way, potentially leading to big changes in technology.
This research is published in Physical Review Letters.