Giant energy product in nanostructured two-phase magnets

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
J.M.D. Coey, Trinity College, Dublin, Ireland

Date of this Version

December 1993

Comments

Published by Am Physical Soc. Phys. Rev. B 48 (1993) 15812-15816. Copyright 1993. Permission to use. http://www.aps.org/.

Abstract

Exchange hardening of nanostructured two-phase systems composed of an aligned hard phase and a soft phase with high magnetization is investigated using an approach which yields analytic nucleation fields from the micromagnetic vector equation, and accounts for interactions between the soft regions. In suitable structures the nucleation field is proportional to the volume-averaged anisotropy constant. For example, a multilayer composed of alternating 2.4 nm hard-magnetic Sm₂Fe₁₇N₃ layers and 9 nm Fe₆₅Co₃₅ layers can have an energy product as high as 1 MJ/m³ (120 MG Oe), with a rare-earth content of only 5 wt %. Giant energy products may also be achieved in suitable cellular and disordered structures.