Discovery of 3rd type of magnetism named physics breakthrough of 2024

Science journal lauded the discovery of altermagnetism by Johannes Gutenberg University Mainz which could revolutionise data storage.

From Johannes Gutenberg University Mainz 30/01/25 (first released 27/01/25)

Science and research make groundbreaking discoveries every day, constantly pushing the boundaries of our knowledge.

Every year, the high-profile academic journal Science names ten of those research achievements in a top list of scientific breakthroughs.

For 2024, Science chose the drug lenacapavir and its potential to reduce HIV/AIDS infections to zero as its Breakthrough of the Year.

In the field of physics, the phenomenon of altermagnetism – discovered by researchers of Johannes Gutenberg University Mainz (JGU) – received the special honor to be listed as another major scientific breakthrough.

“This is a truly unique tribute to our work, and we are proud and honored to receive this acknowledgement for our research,” said Professor Jairo Sinova of the JGU Institute of Physics.

He and his team discovered and demonstrated the phenomenon of altermagnetism.

So far, physics had decided between only two classes of magnetism, namely ferromagnetism and antiferromagnetism.

Even the ancient Greeks knew about ferromagnetism, which makes refrigerator magnets stay in place, for example.

While ferromagnets have all their magnetic moments aligned in the same direction, antiferromagnets have magnetic moments that align in a regular pattern pointing in opposite directions, with the result that the magnetic moments cancel each other out externally.

Theoretical prediction of altermagnetism in 2019

In 2019, researchers at Mainz University came across an effect that they could not explain by either of these types of magnetism: the presence of a fully intact momentum current in antiferromagnets.

They postulated that this must be attributable to an alignment of magnetic moments that was unlike that in ferromagnetism and antiferromagnetism – and with that, the concept of altermagnetism was born.

In effect, altermagnets combine the characteristics of ferromagnets and antiferromagnets.

Their neighboring magnetic moments are always antiparallel to each other, as in antiferromagnets, but, at the same time, they exhibit a spin-polarized current – just like ferromagnets.

“By means of a mathematical analysis of the spin symmetries, we were able to theoretically predict the existence of altermagnetism,” explained Professor Sinova.

“The spin-polarized current alternates with the direction of the current, hence the name ‘altermagnetism’.”

The new field of altermagnetism is at the core of the Collaborative Research Centers CRC/TR 173 “Spin+X – Spin in its collective environment” and CRC/TR 288 “Elastic Tuning and Response of Electronic Quantum Phases of Matter” (ELASTO-Q-MAT), in which JGU researchers play a significant role.

The German Research Foundation approved continued funding for both CRCs in 2024.

Experimental proof in 2024

In 2024, the researchers at JGU also obtained experimental demonstration of altermagnetism.

“Our colleagues in the team of Professor Hans-Joachim Elmers were able to measure for the first time an effect that is considered to be a signature of altermagnetism.”

“They used a specially developed impulse electron microscope at DESY, one of Germany’s largest research centers,” added Sinova.

The discovery of altermagnetism as a third type of magnetism is an important scientific breakthrough because it reveals an effect that was previously unknown but even more so because of the relevance of the practical applications in which it could be used.

Data storage capacity could be substantially increased if it proves feasible to use the magnetic moment of electrons instead of their charge in dynamic random-access memory for data storage.

The big advantage is that there are at least 200 different materials that are currently known to exhibit altermagnetism.