Properties of the low-spin high-spin interface during the relaxation of spin-crossover materials, investigated...

The present work is devoted to the spatio-temporal investigations of spin-crossover lattices during their thermal relaxation from high- to low-spin state. The analysis is performed using Monte Carlo simulations on a distortable 2D lattice the sites of which are occupied by high-spin (HS) or low-spin (LS) atoms. The lattice is circular in shape and the HS to LS transformation results in single domain nucleation followed by growth and propagation processes. The evolution of the LS:HS interface is monitored during the relaxation process, through the mapping of spin states, displacement fields, local stresses, and elastic energy. The results show a curved interface, the curvature of which is reversed at the mid-transformation. The local stresses and elastic energy peak at the vicinity of the HS:LS interface, with sizeable dependence upon the position along the front line which evidences the edge effects.