New Class of Magnetism Imaged for First Time: Altermagnetism | Sci.News

Altermagnetism is a distinct form of magnetic order where the tiny constituent magnetic building blocks align antiparallel to their neighbors, but the structure hosting each one is rotated compared to its neighbors. University of Nottingham’s Professor Peter Wadley and his colleagues have now shown that this new class of magnetism exists and can be controlled in microscopic devices.

Magnetic materials are used in the majority of long term computer memory and the latest generation of microelectronic devices.

This is not only a massive and vital industry but also a significant source of global carbon emissions.

Replacing the key components with altermagnetic materials would lead to huge increases in speed and efficiency while having the potential to massively reduce our dependency on rare and toxic heavy elements needed for conventional ferromagnetic technology.

Altermagnets combine the favorable properties of ferromagnets and antiferromagnets into a single material.

They have the potential to lead to a thousand fold increase in speed of microelectronic components and digital memory while being more robust and m energy efficient.

“Altermagnets consist of magnetic moments that point antiparallel to their neighbors,” Professor Wadley said.

“However, each part of the crystal hosting these tiny moments is rotated with respect to its neighbors. This is like antiferromagnetism with a twist! But this subtle difference has huge ramifications.”

“Our experimental work has provided a bridge between theoretical concepts and real-life realization, which hopefully illuminates a path to developing altermagnetic materials for practical applications,” said University of Nottingham’s Dr. Oliver Amin.

The new experimental study was carried out at the MAX IV international facility in Sweden.

The facility, which looks like a giant metal doughnut, is an electron accelerator, called a synchrotron, that produces X-rays.

X-rays are shone onto the magnetic material and the electrons given off from the surface are detected using a special microscope.

This allows an image to be produced of the magnetism in the material with resolution of small features down to the nanoscale.

“To be amongst the first to see the effect and properties of this promising new class of magnetic materials has been an immensely rewarding and challenging privilege,” said University of Nottingham Ph.D. student Alfred Dal Din.

The team’s work was published in the journal Nature.

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O.J. Amin et al. 2024. Nanoscale imaging and control of altermagnetism in MnTe. Nature 636, 348-353; doi: 10.1038/s41586-024-08234-x