Spintronics — the practice of using electrons to read, write and manipulate data — has long been hailed as a promising avenue for post-CMOS exploration, but imbibing a substrate with the necessary levels of magnetism and conductivity has proved challenging.
A cross-disciplinary team of researchers at the University of Michigan have created a semiconductor compound that is more conducive to this level of control.
The new compound shows promise as a base material for spintronic-based devices, in the same way that silicon is the base for electronic computing devices. It’s a breakthrough that could hold the key to smaller, faster, more energy-efficient computing devices.
Circuits that use spin have a smaller footprint than charge-based circuits, which means that more of them can be squeezed onto a single processor. In this way, spintronic offers a path beyond the physical limits of silicon-based microelectronics. Additionally, spintronics devices store information using the “on” or “off” electrical charge and the “up” or “down” magnetic spin of electrons. This is an advantage because the spin of electrons stays stable at smaller states of miniaturization.
“You can only make an electronic circuit so small before the charge of an electron becomes erratic,” explains Ferdinand Poudeu, assistant professor of materials science and engineering at the University of Michigan “But the spin of electrons remains stable at much smaller sizes, so spintronic devices open the door to a whole new generation of computing.”
Another benefit of spintronics is the ability to combine logic, storage and communication onto a single chip, again enabling a much smaller footprint and lower power consumption.
For years, researchers in the field have sought to make spintronic semiconductors by working to tweak existing materials, but Poudeu’s team went back to the drawing board, and created a new crystal structure made from a mixture of iron, bismuth and selenium. The result is a material that offers the ability to manipulate conductivity and magnetism independently.
Based at the University of Michigan, the project drew from chemistry, crystallography and computer science to create a novel semiconductor spintronics substrate. While the initial research was based on a powder form of the material, the next step will be to manufacture the thin film that would be required for a spintronic device. The process is expected to take about a year.
The team’s research is detailed further in the paper “Coexistence of High-T Ferromagnetism and n-Type Electrical Conductivity in FeBi2Se4,” published in the Journal of the American Chemical Society.