Two-level Ising-like model for spin-crossover phenomenon including the magnetic field effect: the mean-field approximation and Monte Carlo resolutions

C. Consejo (1, 2) , Gábor Molnár (1) , Michel Goiran (2) , Azzedine Bousseksou (1)

1 LCC - Laboratoire de chimie de coordination
2 LNCMP - Laboratoire National des Champs Magnétiques Pulsés

In this paper we analysed the magnetic field effect on the spin-crossover phenomenon using different theoretical approaches: thermodynamic and Ising-like models. This latter, including magnetic field, was treated in the mean-field approximation and—for the first time—by Monte Carlo numerical method. We propose an adaptation of the metropolis algorithm to take into account the different degeneracies of the high and low-spin levels and their Zeeman splitings due to the effect of magnetic field in both states. A comparison of both methods is given and discussed.

Mots clés: Spin-crossover; Bistability; Magnetic field effect; Ising-like model; Monte Carlo

Domaines: Supraconductivité [cond-mat.supr-con]

C. Consejo, Gábor Molnár, Michel Goiran, Azzedine Bousseksou. Two-level Ising-like model for spin-crossover phenomenon including the magnetic field effect: the mean-field approximation and Monte Carlo resolutions. Polyhedron, 2003, 22 (14-17), pp.2441-2446. ⟨10.1016/S0277-5387(03)00293-6⟩. ⟨hal-00015785⟩