J. Phys. IV France 07 (1997) C1-639-C1-640
Theoretical Study of Localized Spin Waves in a Ferrimagnet with ImpuritiesO. Nagai1, M. Kang1, M. Tomita1, Y. Yamada2 and H.T. Diep3
1 Department of Physics, Kobe University, Kobe 657, Japan
2 Department of Management, Kansai Jogakuin Women's College, Miki 673-05, Japan
3 Groupe de Physique Statistique, Université de Cergy-Pontoise, 2 avenue Adolphe Chauvin, 95302 Cergy-Pontoise cedex, France
In this paper, we theoretically investigate the impurity state in a ferrimagnet. We consider a bodycentered cubic crystal based on the model of two sublattices, A-sublattice and B-sublattice. The impurity spin (Si) is assumed to be not located at the interstitial but located at the A-sublattice point or B-sublattice point. Confining our interests to the case of one impurity and one spin-wave, we solve Our problem exactly. We have found several interesting features for our system. For example, the localized spin-wave appears in the band gap only when Si is located at A-sublattice point if SA<SB and the exchange coupling between the impurity spin and the neighboring SB spin is antiferromagnetic.
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