Prior to the ALTERMAG project, the PI’s team was intensely searching for the existence of a hitherto unknown class of magnets that would combine the advantages of ferromagnets and antiferromagnets. Specifically, the team searched for substances that could enable the generation of strong conserved spin currents, like in conventional ferromagnets, while featuring a vanishing magnetization, like in conventional antiferromagnets. Such properties were traditionally considered in physics as mutually exclusive. The research led to the prediction of altermagnets whose exploration is the topic of ALTERMAG.
The anisotropic higher-partial-wave ordering in altermagnets bears physical analogies to the higher-partial-wave ordering in unconventional superfluidity and superconductivity discovered in the 1970s and 1980s. The founders of quantum mechanics have been asking questions about whether such unconventional phases can in principle exist since the 1940s. In superfluidity/superconductivity they were discovered a few decades later, while it took another several decades before the magnetic counterparts were eventually discovered by the PI and collaborators in the form of altermagnetism. Within two years preceding the ALTERMAG project, the PI and collaborators published predictions of the anomalous Hall effect and other spintronic phenomena in altermagnets. Between the submission and the starting date of ALTERMAG, two key works followed. The first one focused on a basic theoretical delineation and description of altermagnetism, and the second one on the broad potential of this unconventional magnetic phase in science and technology. During the first reporting period of the project, the experimental researched started from observations of the anomalous Hall effect. The ALTERMAG team then coordinated research which provided the decisive spectroscopic experimental evidence of altermagnetism. The discovery attracted extraordinary attention not only in the scientific community. Popular articles about altermagnets as a third distinct basic class of magnets were published, among others, in Science, Nature, ScienceNews, The Economist, Newsweek, or The Financial Times. Further spectroscopic evidence of altermagnetism was then provided by the PI and collaborators. In parallel, the prediction and observation of circular dichroism opened a direct way for microscopic imaging of the altermagnetic order. This, together with the control of the altermagnetic order on nanoscale, was demonstrated experimentally. With these and other research highlights, described in more detail in the Scientific Report, the ALTERMAG team has made a significant progress towards all project’s objectives, namely Objective O1 aiming to establish the material basis of altermagnetism, Objective O2 aiming to unravel the unconventional spectroscopy of altermagnets, and Objectives O3 and O4 aiming to demonstrate altermagnetic spintronic functionalities and devices.
