The property that makes fluorescent lights vibrate could power a new generation of more efficient computing devices that store data with magnetic fields rather than electricity.
A team led by researchers at the University of Michigan has developed a material that is at least twice as “magnetostrictive” and much less expensive than other materials in its class. In addition to computing, it could also lead to better magnetic sensors for medical and safety devices.
Magnetostriction, which causes fluorescent lights and electrical transformers to hum, occurs when the shape of a material and the magnetic field are related – that is, a change in shape causes a change in the magnetic field. . Ownership could be the key to a new generation of computing devices called magnetoelectrics.
Magnetoelectric chips could make everything from massive data centers to cellphones much more energy efficient, reducing the power requirements of the global IT infrastructure.
Made from a combination of iron and gallium, the material is detailed in an article published May 12 in Nature communication. The team is led by UM Professor of Materials Science and Engineering John Heron and includes researchers from Intel; Cornell University; University of California, Berkeley; University of Wisconsin; Purdue University and elsewhere.
Magnetoelectric devices use magnetic fields instead of electricity to store the digital ones and zeros of binary data. Tiny pulses of electricity cause them to expand or contract slightly, shifting their magnetic field from positive to negative or vice versa. Because they don’t need a constant flow of electricity like today’s chips do, they use a fraction of the energy.
“A key to making magnetoelectric devices work is to find materials whose electrical and magnetic properties are related.” Said Heron. “And more magnetostriction means a chip can do the same job with less power.”
Cheaper magnetoelectric devices with tenfold improvement
Most of today’s magnetostrictive materials use rare earth elements, which are too rare and too expensive to be used in the amounts needed by computing devices. But Heron’s team found a way to bring in high levels of magnetostriction from cheap iron and gallium.
Usually, Heron explains, the magnetostriction of the iron-gallium alloy increases with the addition of gallium. But these increases stabilize and eventually decrease as the higher amounts of gallium begin to form an ordered atomic structure.
So the research team used a process called low-temperature molecular beam epitaxy to essentially freeze atoms in place, preventing them from forming an orderly structure as more gallium was added. In this way, Heron and his team were able to double the amount of gallium in the material, increasing the magnetostriction tenfold compared to unmodified iron-gallium alloys.
“Low-temperature molecular beam epitaxy is an extremely useful technique – it’s kind of like spray painting with individual atoms,” Heron said. “And ‘spraying’ the material onto a surface that deforms slightly when voltage is applied also made it easier to test its magnetostrictive properties.”
Researchers work with Intel’s MESO program
The magnetoelectric devices manufactured in the study are several microns in size – large by computer standards. But researchers are working with Intel to find ways to shrink them to a more useful size that will be compatible with the company’s magnetoelectric spin-orbit (or MESO) device program, one of whose goals is to push the devices. magnetoelectrics in the mainstream.
“Intel is great at turning things around and making technology work at the very small scale of a computer chip,” Heron said. “They are very invested in this project and we meet with them regularly to get feedback and ideas on how to develop this technology to make it useful in the computer chips they call MESO.”
While a device that uses the material is probably decades away, Heron’s lab has filed for patent protection with the UM Office of Technology Transfer.