Prog. Theor. Phys. Vol. 109 No. 5 (2003) pp. 729-739
Generalized Wajnflasz Model for Charge Transfer Spin-Crossover Phenomena
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)
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.
DOI : 10.1143/PTP.109.729
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Citing Article(s) :
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
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