Research: Metastability of the Skyrmion Lattice in GdRu2Si2 Revealed by Ultrasound

Magnetic skyrmions are nanometric, vortexlike spin structures that represent topological defects of the magnetization. Skyrmion phases appear in certain magnetic materials under applied magnetic fields. Here, the authors investigated metallic GdRu₂Si₂, where skyrmions arise from frustrated and long-range exchange interactions with the skyrmion lattice remaining stable down to low temperatures. Using sound-velocity measurements, the researchers revealed a series of pronounced anomalies. The emergence of hysteresis and steplike features indicate intrinsic metastability of the skyrmion lattice. These findings show that skyrmion lattices can persist and reorganize even in the absence of strong thermal fluctuations.

J. Sourd, D. A. Mayoh, G. Balakrishnan, J. Wosnitza, S. Zherlitsyn, 
Metastability of the Skyrmion Lattice in GdRu₂Si₂ Revealed by Ultrasound,
Phys. Rev. Lett. 137, 066703 (2026)