Ferro-paraelectric transition and thermal hysteresis loop of dielectric permittivity in charge transfer complex

Much attention has been focused on the identification of promising valence tautomeric complexes as switchable molecular materials for potential applications, such as memories, switching devices and sensors. Here we report a dielectric investigation of the charge transfer transition (CT) in three cyanometalate complexes: Rb_0.8Mn[Fe(CN)₆]_0.93 1.62H₂O, Na_2.2Co₄[Fe(CN)₆]_3.3 15H₂O and C_O3[W(CN)₈]₂(pyrimidine)₄ 6H₂O, involving change in their dielectric permittivity and electrical conductivity. The CT phase transition is founded to be coupled to a paraferroelectric transition between the high temperature (HT) and the low temperature phase (LT).