Photo-induced and thermal bistability of spin crossover nanoparticles

Abstract

We predict that the thermal and photo-induced bistability in spin crossover (SCO) core–shell nanoparticles is strongly dependent on the heterostructure geometry. We show that varying the core–shell lattice mismatch allows systematic control of the properties of SCO nanoparticles. We demonstrate a linear relationship between the temperature characterising the photo-induced bistability, T_LIESST, and the thermal spin crossover temperature, T_1/2. This nanostructural approach complements the traditional approach of controlling the relationship between T_LIESST and T_1/2 by making chemical substitutions within families of SCO materials. We give a simple explanation of both relationships. We also demonstrate a non-monotonic dependence of thermal hysteresis width on the shell thickness, which explains a number of apparently contradictory experimental observations.