Regular Article - Solid State and Materials
Magnetic-field induced multi-step transitions in ferromagnetic spin-crossover solids within the BEG model
Département de Physique (FAST) et Institut des Mathématiques et de Sciences Physiques (IMSP), Université d’Abomey-Calavi, BP 613, 01, Porto-Novo, Benin
2 Groupe d’Etudes de la Matière Condensée, Université Paris-Saclay, Université de Versailles/St. Quentin en Yvelines-CNRS, 45 Avenue des Etats Unis., 78035, Versailles Cedex, France
Accepted: 23 November 2020
Published online: 28 January 2021
We study by means of the 2D Blume–Emery–Griffiths (BEG) spin-1 model, spin-crossover (SCO) and prussian blue analogs (PBAs) solids. In this model, the spin states, which can be high-spin (HS) or low-spin (LS), interact magnetically and elastically with their nearest neighbors. To account for the volume change, accompanying the spin transition phenomenon, all interactions through the lattice are assumed as temperature-dependent. In addition, the system is subject to a variable magnetic field lifting the degeneracy in the HS state. A stochastic cooperative dynamics of this BEG-like Hamiltonian, describing the equilibrium and nonequilibrium properties of ferromagnetic spin-crossover solids, is derived from the Glauber approach, with appropriate Arrhenius microscopic transition rates. The model generates under the magnetic field, sigmoidal relaxation and a hysteresis phenomenon of the HS fraction, as well as multistep behavior of the magnetization. These behaviors open the way to new route of multi-stable systems, desired in multi-byte electronics.
© EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021