Altermagnetism: The Quantum Twist Rewriting a Century of Physics

For over a century, physicists operated under a seemingly unshakable understanding of magnetism, categorizing all collinear magnets into one of two fundamental types: ferromagnets or antiferromagnets. This binary view, a cornerstone of condensed matter physics, has now been unequivocally challenged. The recent discovery of altermagnetism, a previously unknown fundamental class of magnetism, has not only overturned this established paradigm but has also opened an entirely new research field with profound implications for quantum materials and future information technologies.

The significance of this breakthrough was underscored by the award of the 2026 Europhysics Prize of the European Physical Society (EPS) Condensed Matter Division to Professor Jairo Sinova, Dr. Libor Šmejkal, and Professor Tomas Jungwirth. Their groundbreaking work establishing altermagnetism as a third elementary form of collinear magnetism was recognized in July 2026 and will be presented in September 2026 at the 32nd General Conference of the European Physical Society Condensed Matter Division in Graz, Austria, celebrating a finding that had remained hidden for over 100 years.

Rewriting the Textbooks: A Century of Assumptions Challenged

The traditional landscape of magnetism was clear. Ferromagnets, like iron, possess a net magnetization due to aligned atomic spins, making them indispensable for magnetic memory. These materials are the foundation of modern magnetic memory technologies but are typically limited to gigahertz speeds. Antiferromagnets, by contrast, have opposing magnetic moments that cancel each other out, resulting in no net magnetization and displaying fundamentally different electronic properties. They appear magnetically silent externally, offering extreme stability and resistance to external magnetic interference, which makes them attractive for ultra-dense memory where crosstalk between bits is a concern. However, their lack of a net magnetic field has historically made them harder to utilize for storage, as sensing their internal state requires specialized methods.

Altermagnetism represents a true hybrid, combining properties of both. Like antiferromagnets, altermagnets possess no net magnetization and thus no external magnetic field. Yet, like ferromagnets, they simultaneously exhibit electronic properties previously thought exclusive to ferromagnets, such as spin-polarized electrical currents. This unique combination is due to a specific twist in their crystal symmetry: while neighboring spins are antiparallel, they are related by a rotation rather than a simple inversion or translation. This allows for highly spin-polarized electrical currents together with ultrafast magnetic dynamics, overcoming the limitations of traditional magnets.

The Promise of a Hidden Magnetic Phase

This novel form of magnetic order offers immense potential, particularly for next-generation spintronic devices. Our current information age heavily relies on electrons' charge for computing and their magnetic spin for data storage. While ferromagnets enabled the digital era, their speed limits (gigahertz) hinder efficient connection to faster terahertz optical communication networks and the Internet of Things. Conventional antiferromagnets, although potentially a thousand times faster, produce signals too weak for practical detection. Altermagnets bridge this gap, combining terahertz speeds with robust spin-polarized signals, providing a new foundation for information technologies.

The initial steps towards this discovery emerged from earlier theoretical work on unconventional magnetic transport phenomena. The researchers recognized that unusual properties, like the crystal anomalous Hall effect, were not isolated material-specific behaviors but reflected an entirely new magnetic phase governed by previously overlooked spin symmetries. Dr. Libor Šmejkal, working at Johannes Gutenberg University Mainz from 2016 to 2024, led the development of many of these theoretical concepts. In 2022, the team introduced the complete symmetry classification of altermagnetism and identified hundreds of candidate materials. Since then, experimental groups worldwide have rapidly confirmed its existence using various techniques, including angle-resolved photoemission spectroscopy (ARPES) and electrical transport measurements. Today, altermagnetism has become one of the fastest-growing research areas in condensed matter physics, with research programs now spanning Europe, North America, and Asia.

Beyond technological applications, the discovery has profound implications for fundamental physics. Altermagnetism establishes a new symmetry class of matter, providing unexpected connections to topological physics, unconventional superconductivity, and strongly correlated quantum materials. It demonstrates that even the most mature scientific fields can still hold fundamental surprises, reshaping our understanding of magnetic order and opening avenues for entirely new research.