Replacing Rare-Earth Elements in Permanent Magnets

Rare earth elements and permanent magnets (invited)

Rare earth (RE) magnets have become virtually indispensible in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high inducti...

Correlations in rare-earth transition-metal permanent magnets

Rare-earth Permanent Magnets: New Magnet Materials and Applications

The introduction of rare-earth permanent magnets based on samarium-cobalt in about 1970, and neodymium-iron-boron magnets in the mid-nineteen eighties, has ushered in a new era in hard magnetic materials. This has resulted in a dramatic improvement in permanent magnet performance, with neodymium-iron-boron (Nd2Fe14B) magnets having a magnetic energy product up to an order of magnitude greater t...

Influence of defect thickness on the angular dependence of coercivity in rare-earth permanent magnets

The coercive field and angular dependence of the coercive field of single-grain Nd2Fe14B permanent magnets are computed using finite element micromagnetics. It is shown that the thickness of surface defects plays a critical role in determining the reversal process. For small defect thicknesses reversal is heavily driven by nucleation, whereas with increasing defect thickness domain wall de-pinn...

In situ non-aqueous nucleation and growth of next generation rare-earth-free permanent magnets.

Using a controllable wet chemical approach, the polyol process, we developed a cobalt carbide nanomagnet consisting of an assembly of Co2C and Co3C nanoparticles as an alternative to rare earth permanent magnets (PMs). The thermodynamically stable mixed phase cobalt carbide nanoparticles are shown to be acicular in morphology. Their exchange-coupled magnetic interaction possessing high maximum ...