Welcome to magnet mania

This trio of breakthroughs in the field of magnetism has both scientific and real-world implications.

In the news

In recent months, magnetism has leapt from the refrigerator door to the headlines.

Let’s start with what’s known as Nagaoka ferromagnetism. The everyday magnets we’re all familiar with are attracted to certain metals that are naturally ferromagnetic because of the way their atomic electrons behave.

In 1966, physicist Yosuke Nagaoka pictured a way to magnetize any material by manipulating electron movement in a hypothetical two-dimensional lattice. For more than half a century, scientists labored to confirm Nagaoka’s idea. In 2020, a team was able to observe the phenomenon in a tiny, highly controlled environment. Now, physicists have advanced this by creating Nagaoka ferromagnetism in a single-layer sheet of atoms that are so thin as to boggle the mind.

Meanwhile, other researchers claim to have proved the existence of a third branch of magnetism called altermagnetism. To oversimplify: Ferromagnet electrons spin in the same direction, which allows for their “stickiness.” Antiferromagnetic materials, by contrast, have electrons that spin in alternating directions, so there’s no net magnetization and no stick.

Now, altermagnets have joined the party, according to an international consortium of researchers working at Swiss Light Source SLS. These magnets feature a certain arrangement of spins and crystal symmetries. As the researchers explain, “the spins alternate, as in antiferromagnets, resulting in no net magnetization. Yet, rather than simply canceling out, the symmetries give an electronic band structure with strong spin polarization that flips in direction as you pass through the material's energy bands—hence the name.”

And in yet more intriguing magnet news, MIT recently announced test results one expert called "the most important thing, in my opinion, in the last 30 years of fusion research." Why fusion? Well, previously, the best superconducting magnets available were deemed powerful enough to potentially achieve fusion energy—but with limitations that rendered them unviable in the real world.

That has changed. The new tests were performed on a type of magnet invented at MIT in 2021 that was made from high-temperature superconducting material and notched a world-record strength of 20 tesla— “the intensity needed to build a fusion power plant that is expected to produce a net output of power and potentially usher in an era of virtually limitless power production.”

The Cognizant take

Some of these magnet developments are scientifically intriguing, while others will have weighty real-world implications. For instance, altermagnets are exciting because of their potential application in the field of spintronics, a vital emerging research area with “immense potential to provide high-speed, low-power and high-density logic and memory electronic devices.” They could lead to advances in lasers, semiconductors and solar cells.

Regarding the news from MIT, the 2021 breakthrough was just the beginning; since then, scientists have been studying the magnet’s components tirelessly. This culminated in six peer-reviewed papers in the March issue of IEEE Transactions on Applied Superconductivity. Bottom line: The studies give the original design a thumbs-up, possibly paving the way for practical fusion power—a game-changer, and that’s understating it.

As for Nagaoka ferromagnetism? Well, practical applications aren’t the only reason to do science; sometimes, the thrill of the hunt is enough. As one member of the research team said, “That’s why I’m doing this kind of research: I get to learn things that we didn’t know before, see things that we haven’t seen before.”