J. Phys. I France 3 (1993) 1463-1473
Ising-like model for the two step spin-crossover of binuclear moleculesA. Bousseksou1, 2, F. Varret1 and J. Nasser1
1 Département de Recherches Physiques UA CNRS n° 71, Université Pierre et Marie Curie, 75252 Paris Cedex 05, France
2 Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex, France
(Received 29 July 1992, revised 3 December 1993, accepted 18 February 1993)
We present a two-sublattice Ising-type model, involving one intramolecular interaction treated rigorously and intermolecular interactions treated in the mean-field approach, in order to describe the two-step transition exhibited by a bi-nuclear spin-crossover complex. Spontaneous symmetry breakings can be obtained according to the relative values of the interactions parameters. The phase diagram is given and the experimental data of [ Fe(bt) (NCS) 2] 2bpym are treated in the present model.
31.30N - 75.90
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