Controlling Skyrmion Lattices via Strain: Elongation, Tilting, and Collapse Mechanisms

TL;DR

This paper presents a comprehensive study combining modeling, simulations, and experiments to demonstrate how strain can control three-dimensional magnetic skyrmion strings, affecting their elongation, tilting, and collapse mechanisms.

Contribution

It introduces a unified framework for strain control of skyrmion strings, revealing mechanisms for elongation, tilting, and collapse, and validates these findings experimentally in a specific magnetic material.

Findings

Strain induces elongation and tilting of skyrmion strings.

Strain drives transition from multi-domain to single-domain states.

Collapse of skyrmion lattice is temperature-dependent and involves anti-cluster formation.

Abstract

This study establishes a comprehensive framework for the three-dimensional strain control of magnetic skyrmion strings. We integrate analytical modeling, micromagnetic simulations, and \textit{in situ} Lorentz transmission electron microscopy experiments to demonstrate that externally applied strain is a powerful stimuli for manipulating three-dimensional magnetic skyrmion strings. Analytical models predict that strain induces both elongation and bidirectional tilting of skyrmion strings in bulk systems, a finding corroborated by numerical simulations. These simulations further reveal that strain drives the system from fragmented multi-domain states toward unified single-domain configurations and facilitates skyrmion string rupture via bobber formation at critical strain levels. The collapse of the skyrmion lattice exhibits a temperature-dependent character, shifting from first-order to second-order behavior near the critical temperature $T_c$. Reducing sample thickness significantly increases the critical strain required for annihilation due to the suppression of tilting. Experimental validation on a $\text{Co}_8\text{Zn}_{8.5}\text{Mn}_{3.5}$ sample confirms strain-induced elongation and subsequent collapse into a conical phase via anti-cluster formation, directly implicating strain-modulated Dzyaloshinskii-Moriya interaction (DMI) as the primary mechanism in this system, over magnetocrystalline anisotropy. These findings provide a mechanistic understanding of strain-mediated control in three-dimensional magnetic systems, demonstrating its feasibility for energy-efficient spintronic applications.