This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers have experimentally demonstrated, for the first time, that it is possible to obtain from an altermagnet a spin current that can transport magnetic information. This result is supported by the theoretical model of electron transport developed by the CFM group.
Altermagnets are a new class of materials that, despite not exhibiting the net magnetization characteristic of conventional magnets, can generate this type of current. The result experimentally confirms a prediction made a few years ago by research groups in the Czech Republic and Germany, and represents an advance in the study of altermagnets and their potential for the development of new information storage and processing technologies. The results of this study have been published in the journal Nature.
The team includes CIC nanoGUNE's Nanodevices Group, in collaboration with the Mesoscopic Physics Group of the Materials Physics Center (CFM) and research groups in the Czech Republic, Germany and France. Altermagnets are a new class of magnetic materials. In conventional magnets, or ferromagnets, the magnetic moments of the atoms point in the same direction.
The sum of these moments creates a net magnetization, which is responsible for the magnetic field we usually associate with a magnet, but which is also used as information in the magnetic memories we use daily in devices such as hard disk drives, servers and magnetic stripe cards. In conventional antiferromagnets, however, the magnetic moments point in opposing directions and cancel each other out, so the material does not exhibit net magnetization, though it does maintain an internal magnetic order. Although antiferromagnets have been known for almost a century, it was only recently that a new class of materials with compensated magnetic moments was identified: the altermagnets.
As with antiferromagnets, altermagnets do not exhibit net magnetization. "This magnetic order still has two possible states, but it is indistinguishable from the outside as it does not generate a magnetic field; the information remains hidden inside the material. However, in these materials, the internal magnetic order affects the behavior of electrons.
This interaction enables the magnetic information to be converted into an electrical signal, thus providing a way to access it," points out Fèlix Casanova, Ikerbasque research professor and leader of the Nanodevices Group at CIC nanoGUNE. To demonstrate it, the research team developed a nanodevice that can extract the magnetic information from the altermagnet and transport it to a detector. CIC nanoGUNE's experience in manufacturing nanoscale devices has been key to this advance, since the spin currents—which transport information associated with the spin orientation of the electrons—retain this information only over very short distances.
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