A research team at Fudan University in Shanghai has achieved a breakthrough in the study of a class of magnetic materials that could help pave the way for faster and more energy-efficient computer chips and memory devices.
The study, conducted by the State Key Laboratory of Surface Physics at Fudan University, was published Thursday on the website of the journal Nature. Researchers say the findings close a long-standing gap between theory and practical use of antiferromagnetic materials, which until now have been considered difficult to control for real-world applications.
Most existing data storage technologies, including hard disk drives and magnetic random-access memory, rely on ferromagnetic materials. These materials store information by switching magnetization directions — commonly described as "up" and "down" — to represent binary data, or 0s and 1s.
But ferromagnetic materials come with inherent limitations. Their strong stray magnetic fields make them vulnerable to interference, which restricts how densely data can be packed. They also tend to operate more slowly and consume more power, problems that have become major obstacles as the chip industry pushes for smaller, faster and more energy-efficient devices.
Antiferromagnets have long been viewed as a promising alternative. In these materials, neighboring magnetic moments point in opposite directions, effectively canceling each other out. As a result, antiferromagnets produce almost no stray magnetic fields, making them more stable and better suited for high-density data storage. They can also switch magnetic states much faster than ferromagnets, offering the potential for significant speed improvements in computing.
Despite these advantages, antiferromagnets have been notoriously difficult to control. Because they lack a net magnetic signal, reliably writing and reading information from them has remained a major technical challenge. As a result, industry experts have often dismissed them as scientifically interesting but impractical for chip development.
The Fudan University team says it has now overcome that hurdle. The researchers found that a special type of low-dimensional, layered antiferromagnet — represented by the material chromium thiophosphate, or CrPS4 — can switch between two stable magnetic states in a predictable way when an external magnetic field is applied. This behavior is similar to that of ferromagnetic materials used in today's memory devices.
"This means we can precisely control the magnetic state and directly observe it using our self-developed magneto-optical microscope, which satisfies the basic requirements for reading and writing binary data," said Wu Shiwei, a professor of physics at Fudan University and a co-corresponding author of the paper.
To explain how the switching works, the team expanded a classic theoretical model — originally developed to describe ferromagnets — so it can also describe this new type of antiferromagnet. Wu said the model provides a solid scientific foundation for future device applications.
Unlike conventional layered antiferromagnets, in which magnetic layers flip one by one and can disrupt the overall magnetic state, the newly studied material switches in an "interlayer-locked" manner. In simple terms, all layers flip together, preserving the stability of the system while maintaining the key advantages of antiferromagnets.
The researchers also proposed a clear criterion that can be used to predict how different antiferromagnetic materials will behave when subjected to magnetic fields. This could help scientists and engineers identify which materials are best suited for use in future chip and memory technologies.
Industry analysts said the advance could support China's push to gain an edge in next-generation semiconductor technologies, potentially reshaping competition in the global information technology sector.
