MIT team advances 2D magnetic materials for green computing

Additionally, the device facilitates robust magnetization switching autonomously, eliminating the requirement for an external magnetic field.

This breakthrough promises groundbreaking prospects for ultra-low power and eco-friendly computing solutions, particularly in big data and artificial intelligence.

Need for energy-efficient equipment 

Thanks to artificial intelligence, the need for computation is growing at a never-before-seen pace on a global scale. As a result, the astounding energy consumption of the global computing infrastructure has raised serious concerns. One of science’s main challenges is creating more energy-efficient computing equipment.

Incorporating magnetic materials into memory and processors offers a feasible route toward creating “beyond-CMOS” computers. These systems have the potential to significantly reduce energy consumption compared to traditional computers.

Transistors are used to represent the 0s and 1s of binary code by switching between open and closed states. According to researchers, magnetization switching could be an alternative to transistors.

Two-dimensional van der Waals magnets present superior properties, enhancing scalability and energy efficiency in magnetic devices. This potentially renders them commercially viable despite prevalent research on bulk materials.

Advancing spin Hall effect

The spin Hall effect is the process by which electrons in heavy metals, such as tantalum or platinum, are separated according to their spin components when an electric current passes through them. This segregation process is material-specific, especially in terms of symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” said Shivam Kajale, a graduate student involved with the project, in a statement.

Conventionally utilized materials, such as platinum, have a form of mirror symmetry in their microscopic structure. This symmetry limits the spin currents to only in-plane spin polarization.

According to the researchers, two mirror symmetries must be broken to create an “out-of-plane” spin component that may be transferred to a magnetic field and cause field-free switching.

“Electrical current can ‘break’ the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane,” said Kajale.

Previously, researchers relied on a small magnetic field to disrupt the second mirror plane in their experiments. To eliminate this need, the team sought tungsten ditelluride, a material with inherent structural properties capable of independently breaking the second mirror plane.

“Because it’s also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” Kajale explained.

Enhancing magnetic efficiency

Magnetic memory and processors consume less energy than silicon-based devices. This is partly due to van der Waals magnets offering superior energy efficiency and scalability.

The lower electrical current density required for magnet switching indicates higher energy efficiency. “The new design has one of the lowest current densities in van der Waals magnetic materials,” said Kajale.

The group is currently investigating comparable low-symmetry van der Waals materials to determine the possibility of lowering current density. They also hope to work with other researchers to figure out how to produce 2D magnetic switch devices on a commercial scale.

The details of the team’s research were published in the journal Science Advances.

Study Abstract

Two-dimensional van der Waals (vdW) magnetic materials hold promise for the development of high-density, energy-efficient spintronic devices for memory and computation. Recent breakthroughs in material discoveries and spin-orbit torque control of vdW ferromagnets have opened a path for integration of vdW magnets in commercial spintronic devices. However, a solution for field-free electric control of perpendicular magnetic anisotropy (PMA) vdW magnets at room temperatures, essential for building compact and thermally stable spintronic devices, is still missing.

Here, we report a solution for the field-free, deterministic, and nonvolatile switching of a PMA vdW ferromagnet, Fe₃GaTe₂, above room temperature (up to 320 K). We use the unconventional out-of-plane anti-damping torque from an adjacent WTe₂ layer to enable such switching with a low current density of 2.23 ? 10⁶ A cm^?2. This study exemplifies the efficacy of low-symmetry vdW materials for spin-orbit torque control of vdW ferromagnets and provides an all-vdW solution for the next generation of scalable and energy-efficient spintronic devices.