Kinetics of light-induced first-order phase transformation in molecular solids: Fe(btr)2(NCS)2∙H2O

International audienceThe mechanism and kinetics of the thermally and light-induced spin transition of the highly cooperative spin crossover material Fe(btr)2(NCS)2∙H2O (btr=4,4'–bis–1,2,4–triazole) have been investigated by single crystal x-ray diffraction techniques. The key role of like-spin domains is quantitatively analyzed through a nucleation, growing, and coarsening mechanism whose kinetics follow the Kolmogorov-Johnson-Mehl-Avrami model with low dimensional characteristics