Synchrotron diffraction studies on spin crossover materials

Spin crossover materials are able to switch reversibly between high spin and low spin states in response to external stimuli including temperature, pressure and light irradiation. The transition between spin states causes a change in color, magnetic and structural properties, leading to potential applications in sensing, display and actuation technologies. Observing the structural changes that occur during a transition is vital to elucidating the mechanism of the phenomenon. From identifying small structural changes to allowing the effects of extreme conditions to be probed in-situ, synchrotron facilities have been invaluable in the understanding of spin crossover systems. However, the sensitivity of these materials to such a diverse range of perturbations means that high-flux X-ray sources may themselves impact upon the spin state of the material. This chapter provides an overview of insights gained through synchrotron diffraction studies on spin crossover materials as well as some perspectives of these challenging experiments.