Permanent magnets are crucial components for (green) energy technologies. Currently, hard magnetic materials based on rare earth elements are mainly used due to their excellent magnetic properties. The stakes are high for this dependence on rare earth elements, as they remain at the top of the EU and US critical minerals list due to their economic importance and supply risk. In a nutshell, there is a need for an innovative research approach to develop rare earth element free magnetic materials.

α-MnBi is a hard magnetic material that is free of rare earth elements. However, two major disadvantages are known. First, the synthesis of sufficient amounts of the α-MnBi phase is a difficult task. In this project, we therefore propose a new approach to processing: cyclic rolling in combination with magnetic annealing.

The second disadvantage is that the α-MnBi phase itself has a low saturation magnetization. This disadvantage is remedied by the synthesis of magnetic nanocomposites with a specific architecture. So far, there is no technological application of magnetic nanocomposites, as this concept has only been successfully applied to thin films or powders. When thinking of applications for electric motors, larger dimensions (at least in the millimeter range) are definitely required. In this project, a new way to produce magnetic nanocomposites in larger dimensions is attempted by processing previously synthesized α-MnBi materials with different magnetic materials.

Ideally, our project will lead to the introduction of a new processing technology for rare-earth element-free magnets. The concept will also make it possible to tailor the magnetic properties. It would be possible to design the material properties so that the magnetic material is best suited for a specific application.