Topological Phase Transformation and Collapse Dynamics of Spin Textures in a Non‐Centrosymmetric D_2d System

Abstract

Recently a large variety of non‐collinear spin textures have been revealed in various crystals with different symmetry groups. Of particular interest are crystals with D2d symmetry that exhibit a complex variety of stable and metastable spin textures that includes antiskyrmions, elliptical Bloch‐skyrmions, fractional‐antiskyrmions, fractional Bloch‐skyrmions, and type‐II trivial‐bubbles. The observation of these structures necessitates their stabilization via magnetic field and temperature protocols which demands a thorough understanding of their creation, transformation, and collapse dynamics. Utilizing the real‐space imaging capabilities of Lorentz transmission electron microscopy, the generation and annihilation of diverse spin textures in a single D2d Heusler compound are demonstrated. It is showed that antiskyrmions and elliptical Bloch‐skyrmions can be deformed into more elaborate elongated magnetic nano‐objects through a collapse mechanism. Their elongation is governed by the intrinsic antisymmetric Dzyaloshinskii‐Moriya vector exchange interaction and dipolar energy present in the system. Furthermore, antiskyrmions are found to be metastable at all temperatures on field‐cooling, while a topological phase transformation from elliptical Bloch‐skyrmions to antiskyrmions rather takes places on field‐heating. These results are corroborated by micromagnetic simulations and demonstrate the efficient manipulation of different spin textures in a D2d compound by varying field and temperature protocols and represents a critical step toward the application of magnetic skyrmions.