Invisible magnetic signals in antiferromagnets can finally be read using a new light-based effect, turning these dead materials into high-speed memory.
April 24, 2026
Original Paper
Optical nonlinear anomalous Hall effect reveals the hidden spin order in antiferromagnets
arXiv · 2604.21802
The Takeaway
Optical nonlinear anomalous Hall effects allow researchers to see and manipulate the magnetic order of antiferromagnets for the first time. These materials have zero net magnetism, making them impossible to read with the sensors used in modern hard drives. This new technique uses light to detect how the internal spin of the atoms is oriented even though they cancel each other out. This discovery opens the door to computers that are 100 times faster than current silicon technology and immune to external magnets. Information could be stored in the hidden geometry of the material electrons rather than a visible magnetic field.
From the abstract
Reading antiferromagnetic order remains a central obstacle for antiferromagnetic memory and logic because zero net magnetisation precludes conventional magnetic readout. Domain imaging typically relies on x-ray magnetic linear dichroism (XMLD) microscopy at synchrotron sources, but XMLD is even under time reversal and cannot distinguish 180°-reversed magnetic states. Here we report the first experimental observation of the optical nonlinear anomalous Hall effect, predicted for antiferromagnets w