Magnetic reversal in Sm₂Fe₁₇N_y permanent magnets

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
K.-H. Müller, IfW Dresden
P.A.P. Wendhausen, IfW Dresden
J.M.D. Coey, Trinity College Dublin, Ireland

Date of this Version

May 1993

Comments

Published by Am Inst of Physics. J. Appl. Phys. J. Appl. Phys. 73 (1993) 6047-6049. Copyright 1993. Permission to use. http://www.aip.org/.

Abstract

Coercivity and nucleation fields for three-dimensional inhomogenities are calculated and discussed. For soft spherical inclusions in a hard magnetic matrix a (δ /R) ² dependence of the nucleation field on inclusion radius R and domain wall width δ has been obtained. To calculate propagation fields for spherical inhomogenities, a nonlinear model has been used. The corresponding coercive field can be much higher than the nucleation field, particularly if the magnitude of the anisotropy changes very steeply. Soft inclusions with sharp interfaces are ineffective at producing complete magnetic reversal. For partly nitrided particles coercivity and nucleation field are predicted to be identical, which is confirmed by experiments on high-performance Sm₂Fe₁₇N_{3- δ} magnets.