Electrical Bistability around Room Temperature in an Unprecedented One-Dimensional Coordination Magnetic Polymer

The
synthesis, crystal structure, and physical properties of an unprecedented
one-dimensional (1D) coordination polymer containing [Fe2(S2C6H2Cl2)4]2– entities bridged by dicationic [K2(μ-H2O)2(THF)4]2+ units are described. The magnetic properties show that the title
compound presents pairwise Fe–Fe antiferromagnetic interactions
that can be well reproduced with a S = 1/2 dimer
model with an exchange coupling, J = −23 cm–1. The electrical conductivity measurements show that
the title compound is a semiconductor with an activation energy of
about 290 meV and two different transitions, both with large hysteresis
of about 60 and 30 K at 260–320 K and 350–380 K, respectively.
These two transitions are assumed to be due to slight structural changes
in the cation–anion interactions. Differential Scanning Calorimetry
confirms the presence of both transitions. This compound represents
the first sample of a coordination polymer showing electrical bistability.