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Micromagnetics of Nanocrystalline Permanent Magnets

Published online by Cambridge University Press:  21 February 2011

T. Schrefl  and
J. Fidler
T. Schrefl
Affiliation:
Institute of Applied and Technical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A- 1040 Vienna, Austria, [email protected]
J. Fidler
Affiliation:
Institute of Applied and Technical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A- 1040 Vienna, Austria
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Abstract

Micromagnetic finite element calculations provide the theoretical limits for the remanence, the coercive field, and the coercive squareness of nanocomposite Nd2Fe14B/α-Fe,Fe3B,Fe23B6magnets. The influence of the intrinsic magnetic properties and the microstructure were investigated using an energy minimization technique. The coercive field reaches a maximum as a function of the average grain size at about 15 nm - 20 nm. The replacement of α-Fe with Fe3B improves the coercive field but deteriorates the loop shape. The reduction of the magnetization and the exchange constant in the soft magnetic Fe3B phase by 20% improves the coercive field without a significant loss in the remanence. An increase of the hard phase anisotropy by 8% enhances the coercive field by more the 100 kA/m in two-phase α-Fe/Nd2Fe14B and by 60 kA/m in two-phase Fe3B/Nd2Fe14B magnets. Dynamic simulations for magnetostatically interacting particles of a bonded magnet show a slight influence of the particle arrangement on magnetization reversal. The interaction field in the range of 100 kA/m to 200 kA/m rapidly decreases the distance from the particle.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 577: Symposium H – Advanced Hard and Soft Magnetic Materials , 1999 , 163
Copyright
Copyright © Materials Research Society 1999

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