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

Some of the best-performing high-temperature magnets are Sm–Co-based alloys with a microstructure that comprises an $$\hbox {Sm}_2\hbox {Co}_{17}$$ Sm 2 Co 17 matrix and magnetically hard $$\hbox {SmCo}_5$$ SmCo 5 cell walls. This generates 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, transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography have been combined with micromagnetic simulations to reveal that the magnetization state in Sm–Co magnets results from curling instabilities and domain-wall pinning effects at the intersections of phases with different magnetic hardness. Additionally, this study has found that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state by acting as nucleation sites for magnetization reversal. These findings reveal previously hidden aspects of magnetism in Sm–Co magnets and, by identifying weak points in the microstructure, provide guidelines for improving these high-performance magnetic materials.

Grinding enhances the magnetic hardness of heterometallic diruthenium(ii,iii) carbonates with a kagome lattice structure

A manual grinding strategy promotes the magnetic hardness of Cs3Cd(H2O)6[{Cd(H2O)3}2{Ru2(CO3)4}3]·10H2O with a kagome lattice structure.

Enhancing magnetic hardness by sonication assisted synthesis of heterometallic carbonato spin-glass Na[Ni(H2O)4Ru2(CO3)4]·3H2O

Sonication assisted synthesis of Na[Ni(H2O)4Ru2(CO3)4]·3H2O promotes its magnetic hardness affected by crystal defect generation.

Epitaxial hard magnetic SmCo5 MFM tips – a new approach to advanced magnetic force microscopy imaging

MFM tips nanofabricated from epitaxial SmCo5 films possess unprecedented magnetic hardness for improved performance in external fields and quantitative analysis.

Effect of composition and coating on the interparticle interactions and magnetic hardness of MFe2O4 (M = Fe, Co, Zn) nanoparticles

Magnetic measurements and Raman spectroscopy of CoFe2O4 particles of 4.4 nm mean size are shown as an illustration.

Development of Effective Technique for Irradiating Samples of Thin Films Using the Focused Ion Beam

In this paper, the technique of irradiation of thin films by Ga+ ions inside of scanning electron microscope, by a focused ion beam is developed. The influence of irradiation on magnetic properties of thin epitaxial films of Co, grown by molecular beam epitaxy in ultrahigh vacuum on a silicon surface with a intermediate layer of copper atoms. It has been shown that low radiation doses lead to an increase of magnetic hardness of the samples. At higher doses, there is a decrease of coercive force, which is apparently due to a change of crystalline structure of the material. An interesting fact is that in the dose range of 1012-1015 the relative remanences is practically unchanged and only at higher doses the magnetic properties of the film worsen.