It’s Official: Mysterious New Form of Magnetism Finally Confirmed

PHYSICS 24 February 2024

By MIKE MCRAE

Ferromagnetism now comes in three varieties. (Libor Šmejkal)

There was a time when there was only one game of ferromagnetism in town. Want to know your north from south? Hold up a compass. Want to stick your electricity bill to the fridge? Bang on a tiny magnetized Garfield gulping down lasagna.

Of course, science had to come and complicate matters by finding a second class of ferromagnetic activity.

Theorized and experimentally demonstrated in the 1930s, antiferromagnetism is like the evil nemesis of the fridge magnet, displaying a similarly stable sub-atomic alignment with a twist that cancels out its stickiness and turns Garfield into the world’s most annoying paper weight.

As confirmed in experiments conducted by a team of researchers from across Europe and in the UK, there’s now yet another type of magnetism that sits in between the two, described as altermagnetism.

“Altermagnetism is actually not something hugely complicated,” says the study’s principal investigator Tomáš Jungwirth, a physicist from the Czech Academy of Sciences.

“It is something entirely fundamental that was in front of our eyes for decades without noticing it.”

Predicted just a few years ago by Jungwirth and some of his fellow researchers, altermagnetism describes alternating energy bands of ferromagnetism and antiferromagnetism that cancel out overall, while still retaining permanent magnetic features on a small, local level.

Granted, an ‘altermagnet’ won’t stick your bills where you won’t forget, either, but we might want to give this new member of the ferromagnetic family a chance – it could be just the thing future electronics needs.

Critical to each of these three magnetic manifestations is a characteristic of quantum objects called spin. Like the rotation of a tiny ball, spin describes a kind of angular momentum, one that exerts a tiny force.