Magnetic Interactions of the Centrosymmetric Skyrmion Material Gd2PdSi3

TL;DR

This study uses neutron scattering to analyze magnetic interactions in Gd2PdSi3, revealing mechanisms that stabilize skyrmions in a centrosymmetric material, aiding future material design.

Contribution

It provides the first detailed experimental characterization of magnetic interactions driving skyrmion formation in Gd2PdSi3, highlighting the roles of RKKY and dipolar interactions.

Findings

RKKY interactions in triangular planes drive skyrmion formation

Large ferromagnetic inter-planar interactions modulated by superstructure

Skyrmions emerge from zero-field helical magnetic order

Abstract

The experimental realization of magnetic skyrmions in centrosymmetric materials has been driven by theoretical understanding of how a delicate balance of anisotropy and frustration can stabilize topological spin structures in applied magnetic fields. Recently, the centrosymmetric material Gd$_{2}$PdSi$_{3}$ was shown to host a field-induced skyrmion phase, but the skyrmion stabilization mechanism remains unclear. Here, we employ neutron-scattering measurements on an isotopically-enriched polycrystalline Gd$_{2}$PdSi$_{3}$ sample to quantify the interactions that drive skyrmion formation. Our analysis reveals spatially-extended interactions in triangular planes that are consistent with an RKKY mechanism, and large ferromagnetic inter-planar magnetic interactions that are modulated by the Pd/Si superstructure. The skyrmion phase emerges from a zero-field helical magnetic order with magnetic moments perpendicular to the magnetic propagation vector, indicating that the magnetic dipolar interaction plays a significant role. Our experimental results establish an interaction space that can promote skyrmion formation, facilitating identification and design of centrosymmetric skyrmion materials.