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noep writes:

There is now a new addition to the magnetic family: thanks to experiments at the Swiss Light Source SLS, researchers have proved the existence of altermagnetism [sciencedaily.com]:

Altermagnets have a special combination of the arrangement of spins and crystal symmetries. The spins alternate, as in antiferromagnets, resulting in no net magnetisation. Yet, rather than simply cancelling 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 altermagnets. This results in highly useful properties more resemblant of ferromagnets, as well as some completely new properties.

Spintronics has promised to revolutionise IT. Typically, ferromagnets have been used as they offer highly desirable, strong, spin-dependent physical phenomena. Yet the macroscopic net magnetisation that is useful in so many other applications poses practical limitations on the scalability of these devices as it causes crosstalk between bits. Instead, Antiferromagnets have been investigated for spintronics, as they have no net magnetisation and thus offer ultra-scalability and energy efficiency. However, the strong spin-dependent effects are lacking, again hindering their practical applicability.

Enter altermagnets with the best of both: zero net magnetisation together with the coveted strong spin-dependent phenomena typically found in ferromagnets -- merits that were regarded as principally incompatible.

- https://www.sciencedaily.com/releases/2024/02/240214122553.htm [sciencedaily.com]

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