Physicists find signs of altermagnetism in Co₁/₄TaSe₂ — ScienceDaily
A research team led by UCF physics professor Madhab Neupane has identified experimental signs of altermagnetism in the layered material Co₁/₄TaSe₂. This type of magnetic order may hold promise for spintronics — technologies that use not only the electric charge of electrons but also their spin. ScienceDaily reports on the study's results.
Combining properties of magnetic states
In ferromagnets, magnetic moments point in one direction and create an overall magnetic field. Such materials can be useful for electronics, but their stray magnetic fields can interfere with nearby components. In antiferromagnets, magnetic moments point in opposite directions and cancel each other out, significantly reducing unwanted fields.
According to the researchers, altermagnets combine certain advantages of both classes. They may produce no unwanted stray magnetic fields while also generating and detecting spin currents — the movement of electron spins through a material. Scientists are studying whether such currents could eventually transmit information in electronic systems.
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How Co₁/₄TaSe₂ was studied
The team investigated the electronic structure of Co₁/₄TaSe₂ using angle-resolved photoemission spectroscopy, known as ARPES. First, the scientists recorded a characteristic splitting of energy levels in the material's electronic bands. They then used spin-resolved ARPES, which showed that the split electronic states have opposite spin polarization — a sign expected for altermagnetism.
The material belongs to the class of transition-metal dichalcogenides and consists of very thin layers that are weakly bound to one another. Magnetic cobalt atoms between the layers influence its unusual magnetic properties. Measurements also indicated that the electronic state associated with altermagnetism originates mainly in the interior of the material, rather than only at the surface.
The researchers view Co₁/₄TaSe₂ as a flexible platform for further study of altermagnetism: the material's properties can be changed and the response of its electronic and magnetic structure can be tracked. At the same time, the mechanism behind the formation of this magnetic state, as well as its interaction with other magnetic phenomena, requires further research.
