Sm(Co,Fe,Cu,Zr)z magnets for high-temperature applications: microstructural and micromagnetic analysis

The microstructure and the microchemistry of Sm(Co,Fe,Cu,Zr)_z permanent magnets determine the domain wall pinning behavior. This work combines nanoanalytical investigations of the precipitation structure with micromagnetic simulations. A cellular precipitation structure, provides pinning centers. Measurements of the thickness of these precipitates by means of transmission electron microscopic image analysis and energy dispersive X-ray spectroscopy reveals that the average thickness is 15-18 nm, which is more than the calculated minimum value of 10 nm. Investigations of the elemental distribution across the precipitates show that the pinning behavior is repulsive.