Internal dipolar field and soft magnons in periodic nanocomposite magnets

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:433

Article

Belemuk, A. M.¹  Chui, S. T.^2,3 

[1] Russian Acad Sci, Inst High Pressure Phys, Troitsk 142190, Russia

[2] Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA

[3] Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA

关键词: Nanocomposite magnets;    Spin waves;    Dipolar interaction;    Remnant magnetization;   

DOI  :  10.1016/j.jmmm.2017.02.051

来源: Elsevier

【 摘 要 】

We study spin wave excitations in a three-dimensional nanocomposite magnet of exchange coupled hard (SmCo5) and soft (FeCo) phases. The dipolar interaction splits the spin wave energies into the upper and lower branches of the spin wave manifold. When the amount of the soft phase is increased the energy of low-lying spin excitations is considerably softened due to two reasons: (i) the low-lying mode locked into the soft phase region with a spin wave gap at k = 0 which scales approximately proportional to the anisotropy constant of the soft phase and (ii) the internal dipolar field which comes from magnetic charges forming at hard-soft boundaries with normals parallel to the magnetization displaces the spin wave manifold toward the lower energies. With adding more soft phase the spin wave gap closes and the system moves to another ground state characterized by the magnetization mismatch between spins of the hard and soft phases. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free