Picoscale Magnetoelasticity Governs Heterogeneous Magnetic Domains in a Noncentrosymmetric Ferromagnetic Weyl Semimetal

TL;DR

This study uses scanning SQUID microscopy to reveal how picometer-level magnetoelastic effects influence magnetic domain heterogeneity in CeAlSi, a noncentrosymmetric ferromagnetic Weyl semimetal, highlighting potential for strain-controlled topological magnetism.

Contribution

It demonstrates the role of magnetoelastic effects in domain formation and manipulation in CeAlSi, advancing understanding of strain effects in topological magnetic materials.

Findings

Identification of metastable and stable magnetic domains in CeAlSi.

Evidence linking domain heterogeneity to magnetoelastic effects.

Potential for strain-based control of magnetic domains in topological systems.

Abstract

Magnetic Weyl semimetals are predicted to host emergent electromagnetic fields at heterogeneous strained phases or at the magnetic domain walls. Tunability and control of the topological and magnetic properties is crucial for revealing these phenomena, which are not well understood or fully realized yet. Here, we use a scanning SQUID microscope to image spontaneous magnetization and magnetic susceptibility of CeAlSi, a noncentrosymmetric ferromagnetic Weyl semimetal candidate. We observe large metastable domains alongside stable ferromagnetic domains. The metastable domains most likely embody a type of frustrated or glassy magnetic phase, with excitations that may be of an emergent and exotic nature. We find evidence that the heterogeneity of the two types of domains arises from magnetoelastic or magnetostriction effects. We show how these domains form, how they interact, and how they can be manipulated or stabilized with estimated lattice strains on picometer levels. CeAlSi is a frontier material for straintronics in correlated topological systems.