Physics Paradigm Challenge

If you push a magnetic wall hard enough with electricity, it’ll actually start moving backward instead of forward.

March 20, 2026

Original Paper

Reversible Steady Domain-Wall Motion Driven by a Direct Current

K. Y. Jing, X. R. Wang, H. Y. Yuan

arXiv · 2603.18722

The Takeaway

In standard physics, the direction of an electrical current determines which way a magnetic boundary moves. This study found that in certain materials, internal inertia allows the boundary to flip direction and move against the flow of electricity, breaking a long-held paradigm in spintronics.

From the abstract

Understanding and manipulating nanoscale domain wall (DW) dynamics is a central topic in magnetism and spintronics for its promising applications in logic and memory devices. In most magnetic systems, inertia affects only transient DW dynamics, while the long-time DW motion is uniquely determined by the magnitude and direction of the applied current. Here we show that this paradigm breaks down in ferrimagnets near the angular momentum compensation point. We demonstrate that a DW can propagate st