Professor Tae-hoon Kim of Chonnam National University’s School of Materials Science and Engineering, in collaboration with the Ames National Laboratory and Iowa State University, has discovered a new mechanism for controlling helical magnetic structures using mechanical stress alone—without relying on an external magnetic field.

Using Lorentz Transmission Electron Microscopy (LTEM), Kim’s team was the first to observe in real time how topological magnetic defects cause reorientation of helical magnetic phases under applied stress. The findings provide the first experimental confirmation of a phenomenon that had previously only been theorized.

The research revealed that the critical stress required to reorient the Q-vector depends on its angle relative to the direction of stress. The structural change occurs through defect dynamics such as “break-and-reconnect” and “dislocation gliding-annihilation”—mechanisms similar to but distinct from plastic deformation in metals. The team further demonstrated that these transitions are driven by anisotropy in stress-induced Dzyaloshinskii–Moriya interaction (DMI), supported by simulation and theoretical modeling.

The discovery lays the foundation for “straintronics,” an emerging field focused on controlling magnetic properties through stress. The technology holds promise for future ultra-low-power spintronic devices, high-density memory, and neuromorphic computing.

The findings were published in the April 2025 issue of Physical Review Letters (Impact Factor: 8.1, JCR top 7.1%).
Paper title: Topological Defect Mediated Helical Phase Reorientation by Uniaxial Stress