  For the study of polarization reversal features in the structure of "mixed
ionic-electronic conductor - on - ferroelectric" type, the hydrogen bonded
molecular ferroelectric crystal triglycine sulphate (TGS) is used. The dynamic
currant-voltage (I-V-) loops of thin TGS plates of polar (010) cut with
dissimilar electrodes on the opposite surfaces (vacuum deposited Ag and
Ag-paste diluted with a water-ethanol mixture) are investigated. After
electroforming in the low-voltage vicinity of coercive voltage, during further
cycling, a reversible transformation of I-V-loop shape occurs from typical of
non-linear dielectrics to typical of memristive systems and than to typical of
ferroelectrics (and vice versa) with a sequential increase (decrease) of
drawing voltage amplitude. Such "awakening" and "falling asleep" of I-V-loops
of the memristor type is apparently associated with reversible electromigration
and accumulation of charged species (e.g., protons), in the hydrated surface
layer of TGS as a component of electrochemical capacitor-on-ferroelectric
structure. The observed transformation can be explained by considering the
coupled ion transfer and polarization reversal taking into account the swinging
of the boundary of the built-in chemical inhomogeneity under conditions of
linear and/or nonlinear dynamics of ion drift and ionic concentration
polarization caused by charged species transfer under the applied voltage.
