For many years, physics studies focused on two main types of magnetism, namely ferromagnetism and antiferromagnetism. The first type entails the alignment of electron spins in the same direction, while the latter entails the alignment of electron spins in alternating, opposite directions.

Yet recent studies have discovered a new kind of magnetism, referred to as altermagnetism, which does not fit into either of the previously identified categories. Altermagnetism is characterized by the breaking of time-reversal symmetry (i.e., the symmetry of physical laws when time is reversed) and spin-split band structures, in materials that retain a zero net magnetization.

Researchers at the Chinese Academy of Sciences and other institutes in China recently uncovered a new material that exhibits altermagnetism at room temperature, namely KV₂Se₂O. Their findings, published in Nature Physics, highlight the promise of KV₂Se₂O both for the study of altermagnetism and for the development of spintronic devices.

Lacquers, paint, concrete—and even ketchup or orange juice: Suspensions are widespread in industry and everyday life. By a suspension, materials scientists mean a liquid in which tiny, insoluble solid particles are evenly distributed. If the concentration of particles in such a mixture is very high, phenomena can be observed that contradict our everyday understanding of a liquid. For example, these so-called non-Newtonian fluids suddenly become more viscous when a strong force acts upon them. For a brief moment, the liquid behaves like a solid.

This sudden thickening is caused by the particles present in the suspension. If the suspension is deformed, the particles have to rearrange themselves. From an energy perspective, it is more advantageous if they roll past each other whenever possible. It is only when this is no longer possible, e.g., because several particles become jammed, that they have to slide relative to each other. However, sliding requires much more force and thus the liquid feels macroscopically more viscous.

The interactions that occur on a microscopically small scale therefore affect the entire system and they determine how a suspension flows. To optimize the suspension and specifically influence its flow characteristics, scientists must therefore understand the magnitude of the frictional forces between the individual particles.

For centuries, humans have made use of glass in their art, tools, and technology. Despite the ubiquity of this material, however, many of its microscopic properties are not well understood, and it continues to defy conventional physical description.

Enter Koun Shirai of the University of Osaka. In an article published in Foundations, Shirai bridges conventional physical theory and the study of nonequilibrium materials to provide a robust description for the thermodynamics of glasses.

Most materials exist in an equilibrium state, meaning that the forces and torques on the material’s atoms are all balanced. Glasses, however, are a famous exception: they are amorphous solid materials whose atoms are always rearranging, albeit very slowly, toward an equilibrium state but do not exist in equilibrium.