Observation of a thermal hysteresis loop in the dielectric constant of spin crossover complexes: towards molecular memory devices

Spin crossover materials made of metallo-organic/inorganic molecular complexes present magnetic susceptibility and optical reflectivity hysteresis due to an internal high-spin (HS) to low-spin (LS) cooperative spin transition with potential applications in memory, display and switching devices. Here, we report the first observation of a thermal bistability in the dielectric constant as a consequence of the HS LS transition. Better than magnetic susceptibility or optical reflectivity, this electrical property allows the effective use of such molecular materials for electronics based memories.