Multicomponent permanent magnets for enhanced electrical device efficiency

Abstract Magnetic remanence (Br) and coercivity (Hc) of hard magnets play a crucial role in electro-mechanical devices like electrical motors or generators. Elevated remanence ensures high efficiency of the device, and large coercivity protects the magnet from demagnetization. Usually, the increase of one comes at the cost of the other, such that the material optimization has a trade-off character. In this work, we demonstrate that in many electrical machines which use permanent magnets, high coercivity is required mainly at the edges of the magnet. This enables us to design a novel form of a permanent magnet, called a multicomponent magnet, where the sides of the magnet have high coercivity, while the central part is characterized by high remanence. Such multicomponent magnets are realized by two independent methods, namely, conventional high-temperature sintering and Spark Plasma Sintering (SPS). The magnetic and mechanical performances are suitable for applications, and simulation results using the magnetic characteristics of the multicomponent geometry predict its benefit on the device functionality. Further tuning of the geometry of the multicomponent permanent magnets opens avenues for promising applications, particularly in electrical motors for electrical vehicles.