Localized magnetic excitations of coupled impurities in a Heisenberg ferromagnet: Optical defect modes

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:323

Article

Leite, R. V.¹  Hidalgo, A. A.¹  Milton Pereira, J., Jr.²  Costa Filho, R. N.² 

[1] Univ Fed Piaui, Dept Fis, Teresina, Piaui, Brazil

[2] Univ Fed Ceara, Dept Fis, Fortaleza, Ceara, Brazil

关键词: Heisenberg ferromagnet;    Green's function;    Spin wave;    Impurity mode;   

DOI  :  10.1016/j.jmmm.2011.02.005

来源: Elsevier

【 摘 要 】

A Green's function method is used to obtain the spectrum of excitations of two neighboring impurities in a semi-infinite ferromagnet. The equations of motion for Green's functions are determined in the framework of the Heisenberg model. The energies of non-resonant localized modes are calculated as a function of the interaction parameters for the exchange coupling between impurity-spin pairs, host-spin pairs, and impurity-host neighbors, as well as the effective field parameter at the impurity sites. With two impurities the system is less symmetric and has more localized modes when compared with a single impurity case. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free