Magnetic domains and structural stability in nanoplates of the rare-earth permanent magnet
Phys. Rev. Applied 25, 064020 – Published 4 June, 2026
DOI: https://doi.org/10.1103/gmm2-7346
Abstract
As one of the key frontiers of technological development in the modern world, rare-earth permanent magnets are now required to have a high maximum energy product and a Curie temperature, so as to meet the needs of today’s environmentally friendly technologies and applications. is a promising rare-earth permanent magnet phase with a theoretical magnetic energy product of ≈59 MGOe, comparable with ––, and it contains no scarce heavy rare earths. The Curie temperature reaches 749 K and the corrosion resistance is excellent, making it suitable for high-temperature, high-stability applications. To understand magnetic properties and phase stability of at high temperatures, we extracted a single-crystal nanoplate from powders and systematically investigated the evolution of the magnetic domains with temperature using advanced in-situ microscopy techniques and micromagnetic simulations. As the temperature increases from room temperature to 575 K, the nanoplates exhibit scalable mazelike magnetic domains, which is a reversible process driven by temperature-dependent magnetocrystalline anisotropy. When the temperature is further increased to 675 K, an irreversible domain evolution occurs, characterized by the formation of stripy magnetic domain walls and magnetic vortices. This phenomenon is associated with nitrogen escape from the lattice at the nanoscale due to its smaller activation energy (∼0.52 eV). The crystal structure remains stable until the temperature exceeds 675 K, at which point decomposition leads to the disappearance of the magnetic domains, indicating that the nitride nanomagnet exhibits promising thermal stability. This work advances the understanding of phase and magnetic stability in rare-earth nitrides, launching them as a promising platform for high-performance permanent magnetic applications.
