Atomistic simulations of α-Fe/Nd2Fe14B magnetic core/shell nanocomposites with enhanced energy product for high temperature permanent magnet applications

Nd 2 Fe 14 B has generated significant interest since its discovery in the 1980s due to its impressive energy density, which makes it a prime candidate for use in permanent magnet applications. Its performance is known to suffer greatly at the high temperatures required for motor applications around 450K. Core/shell nanocomposites provide a potential route to improve material performance by combining the highly anisotropic permanent magnet with a material with high moment and high Curie temperature. We have used an atomistic spin model to investigate the magnetic properties of Nd2Fe14B with α-Fe in a core/shell nanostructure. We find that at typical motor operating temperatures, increasing α-Fe content reduces the coercivity of the system while enhancing the saturation magnetization. The overall effect is that an improvement in BHmax is seen with increasing α-Fe up to an optimal value of 70vol.%. This property of core/shell nanostructures would make them a suitable substitute for pure Nd2Fe14B while simultaneously lowering the raw material cost of the permanent magnet component of high-performance motors.