Aligned two-phase magnets: Permanent magnetism of the future? (invited)

Authors

• Ralph Skomski, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

November 1994

Comments

Published by Am Inst of Physics. J. Appl. Phys. 76 (1994) 7059-7064. Copyright 1994. Permission to use. http://www.aip.org/.

Abstract

Micromagnetic calculations are used to investigate coercivity and energy products of magnets consisting of an aligned hard-magnetic skeleton phase and a soft-magnetic phase with high saturation magnetization. Compared to the present-day theoretical limit of 516 W/m³ for single-phase Nd₂Fe₁₄B, the energy product in suitable nanostructured Sm₂Fe₂N₃/Fe₆₅Co₃₅ composites is predicted to be as high as 1090 kJ/m3. The influence of the skeleton’s texture and shape is discussed, and aligned nanocrystalline two-phase magnets are compared with remanence-enhanced isotropic magnets. In particular, it is shown how the nucleation-based analytical approach breaks down in the isotropic limit. Finally, we outline conceivable processing methods and discuss potential applications of “megajoule” magnets.