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Prog. Theor. Phys. Vol. 109 No. 5 (2003) pp. 729-739

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Generalized Wajnflasz Model for Charge Transfer Spin-Crossover Phenomena

Seiji Miyashita1,* and Norimichi Kojima2,**

1Department of Applied Physics, Graduate School of Engineering,
The University of Tokyo, Tokyo 113-8656, Japan
2Department of Basic Science, Graduate School of Arts and Sciences,
The University of Tokyo, Tokyo 153-8902, Japan

(Received January 8, 2003)

Abstract:

A kind of spin-crossover phenomena associated with charge transfer has been found in (n-C3H7)4N [Fe IIFe III(dto)3], where dto represents C2O2S2. The properties of this phase transition are studied in a generalized Wajnflasz model. The fraction of the high temperature phase configuration is obtained as a function of the temperature. In the high temperature limit, the fraction is 1/(1+√3/5), and it decreases smoothly to zero as the temperature decreases, if we consider free migration of electrons. When a repulsive interaction between the domains of the high temperature and low temperature phases exists, this fraction exhibits a first-order transition at a certain temperature. The temperature dependences of the susceptibility and the magnetic phase transition in the low temperature phase are also investigated. It turns out that a magnetic phase transition in the low temperature phase is induced by fluctuations of the high temperature phase.


URL : http://ptp.ipap.jp/link?PTP/109/729/
DOI : 10.1143/PTP.109.729


*E-mail: miya@spin.t.u-tokyo.ac.jp
**E-mail: cnori@mail.ecc.u-tokyo.ac.jp

[ Full Text PDF : FREE ACCESS (221K) ] Citation:


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Citing Article(s) :

  1. Journal of the Physical Society of Japan 74 (2005) Supplement pp. 103-106 :
    Mechanisms of Magnetic Order in a Charge Transfer Complex Mediated by Virtual Interactions Due to the Charge Fluctuation
    Yusuke Konishi and Seiji Miyashita
  2. Progress of Theoretical Physics Vol. 114 No. 4 (2005) pp. 719-735 :
    Structures of Metastable States in Phase Transitions with a High-Spin Low-Spin Degree of Freedom
    Seiji Miyashita, Yusuke Konishi, Hiroko Tokoro, Masamichi Nishino, Kamel Boukheddaden and François Varret