journal article
Open Access Collection
Unconventional magnetization textures and domain-wall pinning in Sm-Co magnets
Pierobon, Leonardo;Kovács, András;Schäublin, Robin E.;Gerstl, S. S. A.;Caron, J.;Wyss, Urs;Dunin-Borkowski, Rafal E.;Löffler, Jörg F.;Charilaou, Michalis
2019 Condensed Matter
doi: 10.1038/s41598-020-78010-0pmid: 33273594
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.