# Unconventional magnetization textures and domain-wall pinning in Sm-Co magnets

## TL;DR

This study uncovers the complex magnetization processes in Sm-Co magnets, highlighting the role of unconventional domain structures and pinning effects, which are crucial for optimizing high-temperature magnetic performance.

## Contribution

It integrates advanced microscopy, tomography, and simulations to reveal the interplay of curling instabilities and domain-wall pinning in Sm-Co microstructures, offering new insights into magnetic behavior.

## Key findings

- Magnetization involves curling instabilities and pinning at soft-hard interfaces.
- Topologically non-trivial magnetic domains influence magnetic states.
- Microstructure-magnetism coupling is key to magnetic hardness.

## Abstract

The most powerful magnets for high temperature applications are Sm-Co-based alloys with a microstructure that combines magnetically soft and hard regions. The microstructure consists of a dense domain-wall-pinning network that endows the material with remarkable magnetic hardness. A precise understanding of the coupling between magnetism and microstructure is essential for enhancing the performance of Sm-Co magnets, but experiments and theory have not yet converged to a unified model. Here, we combine transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography with micromagnetic simulations to show that the magnetization processes in Sm-Co magnets result from an interplay between curling instabilities and pinning effects at the intersections between magnetically soft and hard regions. We also find that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state. Our findings reveal a previously hidden aspect of magnetism and provide insight into the full potential of high-performance magnetic materials.