A fluctuation-free pathway for a topological magnetic phase transition

TL;DR

This paper reveals a new, fluctuation-free pathway for creating topological magnetic textures through a sequence of symmetry-breaking phase transitions triggered by excitation, enabling rapid and low-energy spin texture generation.

Contribution

It introduces a deterministic cascade of phase transitions leading to topological textures, bypassing fluctuation-driven nucleation, applicable to low-anisotropy magnetic materials.

Findings

Demonstrated a fluctuation-free pathway for topological texture formation

Identified a sequence of phase transitions including second-order and first-order events

Showed the pathway's applicability across various low-anisotropy materials

Abstract

Topological magnetic textures are particle-like spin configurations stabilized by competing interactions. Their formation is commonly attributed to fluctuation-driven, first-order nucleation processes requiring activation over a topological energy barrier. Here, we demonstrate an alternative barrier- and fluctuation-free pathway for nucleating topological magnetic textures, triggered in our experiments by an excitation-induced spin reorientation transition. By combining x-ray imaging, scattering and micromagnetic simulations, we show that the system follows a deterministic cascade of symmetry-breaking phase transitions after excitation. First, the system undergoes a second-order phase transition from a homogeneous state to weak stripe domains, then a first-order transition to topologically trivial bubbles, and finally a topological switching event into skyrmionic textures. Through simulations, we generalize our findings and demonstrate that this pathway is active in a vast range of low-anisotropy materials. This previously unrecognized, spontaneous transition pathway suggests strategies for rapid, low-energy generation of topological spin textures and points to a general role of intrinsic modulational instabilities in phase transitions beyond magnetism.