Making use of the Rugh's dynamical and micro-canonical approach to temperature, we study theclassicalmodel of three dimensional spin-crossover compounds. These compounds are characterized by magnetic ions that can bein a high-spin or low-spin state. We consider the case of diamagnetic low-spin state which are appropriate for Fe-Cocompounds. The values of the magnetization average and fraction of high-spinllow-spin are studied over a wide range ofvalues for the system size, temperature, magnetic field, nearest neighbor coupling and exchange interaction. We alsoaddress metastability according to the relative values of interaction parameters and the phase diagram of the model.Keywords: Phase transition, dynamical temperature, spin crossover.PACS: 05.1O.Ln; 05.50.+q; 07.05.Tp; 75.10.Hk; 75.60.Ej. W. B. Nurdinl and K. D. Schotte21Laboratory of Theoretical and Computer, Department of Physics, FMIPA,University Hasanuddin, Makassar 90245, Indonesia2Fachbereich Physik, Freie Universitaet, Berlin 13353, Germany
