# Interface‐Induced Stability of Nontrivial Topological Spin Textures: Unveiling Room‐Temperature Hopfions and Skyrmions

## TL;DR

Researchers observed stable 3D and 2D magnetic spin structures at room temperature, which could lead to more efficient data storage and processing.

## Contribution

First room-temperature observation of stable hopfions and skyrmions in a trilayer structure without external magnetic fields.

## Key findings

- Skyrmion-hopfion spin textures were observed at room temperature in a EuS-Bi2Se3-EuS trilayer.
- Micromagnetic modeling confirmed the role of interfacial interactions in stabilizing these structures.
- The study shows how geometric confinement and surface electrons control topological spin states.

## Abstract

Topological spin configurations, such as soliton‐like spin texture and Dirac electron assemblies, have recently emerged in fundamental science and technology. Achieving stable topological spin textures at room temperature is crucial for their use as long‐range information carriers. However, their creation and manipulation are hindered by multi‐step field training and competing interactions. Thus, a spontaneous ground state for multidimensional topological spin textures is desirable, with skyrmions forming swirling, hedgehog‐like spin structures in two dimensions and hopfions as their twisted 3D counterparts. Here, the first observation of robust and reproducible topological spin textures of hopfions and skyrmions observed at room temperature and in zero magnetic field is reported, which are stabilized by geometric confinement and protected by interfacial magnetism in a ferromagnet/topological insulator/ferromagnet trilayer heterostructure. These skyrmion‐hopfion configurations are directly observed at room temperature with Lorenz transmission electron microscopy. Using micromagnetic modeling, the experimental observations of hopfion‐skyrmion assemblies are reproduced. This model reveals a complete picture of how spontaneously organized skyrmion lattices encircled by hopfion rings are controlled by surface electrons, uniaxial anisotropy, and Dzyaloshinskii‐Moriya interaction. This study provides evidence that topological chiral spin textures can facilitate the development of magnetic topological carriers, paving the way for ultralow‐power and high‐density information processing.

The first room‐temperature, zero‐field observation of stable skyrmion–hopfion spin textures in EuS─Bi2Se3─EuS trilayers is reported. Combining Lorentz TEM imaging and micromagnetic modeling, the authors unveil how interfacial Dzyaloshinskii–Moriya interaction and geometric confinement stabilize these multidimensional topological states. These findings offer a pathway toward ultralow‐power spintronic devices harnessing robust, chiral magnetism in engineered topological heterostructures.