Atomic structure and domain wall pinning in samarium-cobalt-based permanent magnets

Authors: Michael Duerrschnabel, Min Yi, Kaan Uestuener, Moritz Liesegang, Matthias Katter, Hans-Joachim Kleebe, Bai-Xiang Xu, Oliver Gutfleisch and Leopoldo Molina-Luna

A higher saturation magnetization obtained by an increased iron content is essential for yielding larger energy products in rare-earth Sm2Co17-type pinning-controlled permanent agnets. These are of importance for high-temperature industrial applications due to their intrinsic corrosion resistance and temperature stability. Here we present model magnets with an increased iron content based on a unique nanostructure and -chemical modification route using Fe, Cu, and Zr as dopants. The iron content controls the formation of a diamond-shaped cellular structure that dominates the density and strength of the domain wall pinning sites and thus the coercivity. Using ultra-high-resolution experimental and theoretical methods, we revealed the atomic structure of the single phases present and established a direct correlation to the macroscopic magnetic properties. With further development, this knowledge can be applied to produce samarium cobalt permanent magnets with improved magnetic performance.

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