Magnetic Imaging of Macroscopic Spin Chirality Flipping

TL;DR

This study uses high-resolution magnetic x-ray scattering to visualize and understand the macroscopic flipping of spin chirality in a topological magnet, revealing the role of magnetoelastic coupling and chiral memory effects.

Contribution

It demonstrates the first direct imaging of macroscopic spin chirality reversal and uncovers the influence of charge density waves and magnetoelastic interactions in this process.

Findings

Identified a macroscopic chirality flipping transition.

Discovered a chiral memory effect linked to charge density waves.

Showed magnetoelastic coupling stabilizes topological magnetic states.

Abstract

Chirality is a fundamental organizing principle of correlated and topological states. In quantum magnets, chirality arises from the geometric twisting of spins and serves as an emergent source of Berry curvature and quantum metrics. Although external fields can reversibly tune the spin chirality, understanding how spontaneous reversal occurs on macroscopic length scale remains an unresolved challenge. In this letter, we use resonant magnetic x-ray scattering with 2.5-micron spatial resolution to image intertwined spin, charge, and lattice orders of the correlated topological magnet EuAl4. We uncover a macroscopic chirality flipping transition and a remarkable chiral memory effect. The chiral magnetic domain tracks the landscape of the underlying charge density wave, implicating emergent chiral magnetic interactions arising from competing chiral and nematic lattice fields. Our results reveal the fundamental significance of magnetoelastic coupling in stabilizing homochiral and topological magnetic states.