Atomistic simulations of <i>α</i>-<i>Fe</i>/Nd2Fe14B magnetic core/shell nanocomposites with enhanced energy product for high temperature permanent magnet applications
S. C. Westmoreland, Connor Skelland, Tetsuya Shoji, Masao Yano, Akira Kato, Masaaki Ito, G. Hrkac, T. Schrefl, Richard F. L. Evans, R.W. Chantrell
Abstract
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.