Effect of uniaxial stress on helimagnetic phases in the square-lattice itinerant magnet EuAl$_{4}$

TL;DR

This study explores how uniaxial stress influences the complex helimagnetic phases in EuAl$_{4}$, revealing stress-induced changes in magnetic properties and the role of Fermi-surface nesting in phase stability.

Contribution

It demonstrates the effects of uniaxial stress on magnetic phases and provides first-principles evidence linking lattice distortion to magnetic modulation in EuAl$_{4}$.

Findings

Compressive stress enhances antiferromagnetic character.

Stress shortens the magnetic modulation period.

Fermi-surface nesting is crucial for magnetic phase stability.

Abstract

We investigate uniaxial-stress effects on the magnetic phase diagram of the square-lattice itinerant magnet EuAl$_{4}$, where strong coupling among spin, lattice, and charge produces a variety of helimagnetic phases, including rhombic and square skyrmion lattices. Combining resistivity and magnetization measurements with neutron scattering, we find that compressive stresses of only several tens of megapascal along [010] enhance antiferromagnetic character and shorten the magnetic modulation period in the lowest-temperature single-Q spiral state, thereby driving the critical temperatures and fields of multiple phases to higher values. First-principles calculations show that increasing orthorhombic lattice distortion deforms the Fermi surface relevant to the magnetism, providing compelling evidence that Fermi-surface nesting plays a crucial role in stabilizing the helical magnetic modulations in EuAl$_{4}$.