A new spin on an old superconductor means that it can be an ideal spintronic material, too

Back in the 1980s, researchers discovered that a bismuthate oxide material was a rare type of superconductor that could operate at higher temperatures. Now, a team of engineers and physicists at the University of Wisconsin-Madison has found the material, “Ba(Pb,Bi)O3,” is unique in another way: It exhibits extremely high spin orbit torque, a property useful in the emerging field of spintronics.

The combination makes this and similar materials potentially important in developing the next generation of fast, efficient memory and computing devices.

The finding was an encouraging surprise to Chang Beom-Eom, a professor of materials science and engineering, and Mark Rzchowski, a professor of physics, both at UW-Madison. “We’re looking to expand the range of materials that can be used in spintronic applications,” says Rzchowski. “We had known from previous work these oxides have a lot of interesting properties, and so were investigating the spintronic characteristics. We weren’t anticipating such a large effect. The origins of this are not theoretically understood, but we can speculate about some interesting physical mechanisms.”

The paper was published Dec. 5, 2023, in the journal Nature Electronics.

In conventional electronics, positive and negative electric charges are used to flip millions or billions of tiny transistors on semiconductor chips or in memory devices. But in spintronics, magnetic fields, and interactions with other electrons, manipulate a fundamental property of electrons called the spin state, which records information. This is much faster, more energy-efficient and more powerful than current semiconductors and will advance the development of quantum computing and low-power devices.

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Featured image caption: Chang Beom-Eom, a professor of materials science and engineering, and Mark Rzchowski, a professor of physics, in the lab. Photo: Joel Hallberg.