Post-silicon computing gets one step closer

As electronics soak up a larger and larger share of the world’s electricity, researchers are looking for ways to get more computing done with less power. And some believe that new semiconductors that use a combination of electricity and magnetism to store information could be the answer.

The new materials could make it possible to store the strings of 1’s and 0’s that make up binary code in magnetic instead of electronic switches, eliminating the need for a constant electrical current. They would require only brief pulses of electricity to “flip” the switch from 1 to 0 or vice versa.

These post-silicon electronics would require new semiconducting alloys whose conductive and magnetic properties can be dialed in independently. Now, University of Michigan materials science and engineering professor John Heron has taken a step in that direction.

In a recent study, Heron’s lab showed that the magnetic properties of an advanced material called an “entropy-stabilized oxide” can be manipulated by slightly changing the proportion of metals in the mix. They were able to swing the magnetic properties of a salt-based oxide by up to 65% simply by changing the amount of copper added to the mixture. The findings are detailed in a paper published in Physical Review materials.

“We’ve essentially found a new knob to turn in the development of new semiconductors,” Heron said. “Nobody knew whether you could make an entropy-stabilized oxide with stable, predictable magnetic properties. And we’ve not only shown that, we’ve also shown that you can tune those properties just with small changes in the material’s composition.”

We’ve essentially found a new knob to turn in the development of new semiconductors”

John Heron, assistant professor of materials science and engineering

The next step is to show that the electrical properties of high-entropy oxides can be similarly manipulated. And Heron believes that’s on the horizon based on the lab’s work in the current paper.

Entropy-stabilized oxides are metal mixtures that contain as many as eight different elements instead of an ordinary alloy’s two or three. They break the rules of traditional materials science by piling many elements into a single alloy, creating disorder, or entropy. In the stereochemical chaos, the material begins to make its own rules, creating order from disorder and opening the door to a new world of alloys that are far more tunable and versatile.

The paper is titled “Magnetic frustration control through tunable stereochemically-driven disorder in entropy-stabilized oxides.” It was published October 28, 2019 in Physical Review Materials.