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 greater than or less than LS transition. Better than magnetic susceptibility or optical reflectivity, this electrical property allows the effective use of such molecular materials for electronics based memories.