The team directly observed a unique property in an altermagnetic candidate material, delivering key evidence of a new phase of magnetism first postulated in 2022.
Key takeaways:
- The scientific case for a third type of magnetism – termed “altermagnetism” – has been building over recent years.
- Now, a SLAC-led team has experimentally proven that a material exhibits characteristics that are theoretically impossible to explain without altermagnetism.
- Altermagnetic materials could be used to design advanced electronics, with applications including quantum technologies, memory devices and data centers.
For decades, physicists recognized only two types of magnetism that occur in materials without external influence: ferromagnetism and antiferromagnetism. Today, in findings published in Science, a team led by the U.S. Department of Energy’s SLAC National Accelerator Laboratory has delivered conclusive experimental proof of a third magnetic phase called altermagnetism.
“In the past few years, scientists have observed phenomena that don’t fit neatly into the ferromagnetism-antiferromagnetism dichotomy,” explained lead author Daniel Jost, associate scientist at SLAC and Stanford Institute for Materials and Energy Sciences. “Researchers have been compiling evidence of a third type of magnetism that bridges the qualities of these two classes. We believe our results provide robust experimental confirmation that this third phase – altermagnetism – is real.”
Building on previous studies, this research confirmed that manganese telluride (MnTe) is an altermagnet – a new class of magnet that exhibits properties of both ferromagnetism and antiferromagnetism. Their results showed direct experimental evidence of chirality – an asymmetric magnetic structure, akin to a spiral staircase or a screw – in the spins of an altermagnetic candidate material.
Identifying these unique materials could allow researchers to manipulate their properties in ways that make them ideal candidates for advanced electronics, with applications including quantum technologies, memory devices and data centers.
A primer on magnetism
To most of us, magnetism is a tangible force: It’s what holds a child’s artwork to a refrigerator door and points a compass needle north. But to a physicist, magnetism is more complex. It’s a quantum property of a material, and not all magnetic materials have a directly observable magnetic effect.
In physics, a material is considered magnetic if its electrons’ spins – their internal angular momentum, which can be either “up” or “down” – are polarized, or ordered in a specific pattern.
In ferromagnets, all electronic spins point the same direction (up-up-up or down-down-down), creating an observable magnetic field. Humans have known about and made use of this class of magnets since ancient times. In 1933, scientists discovered another type of material with polarized spins. Antiferromagnets have alternating electronic spins (up-down-up-down) that cancel each other out, producing no net magnetic effect.
Read more on the SLAC website