Unusual memory effects in an incommensurate phase of the TlInS2 ferroelectric semiconductor

The experimental data on memory effects in an incommensurate phase are analyzed both in undoped layered TlInS 2 crystals selected from different technological batches and in TlInS 2 : La. Various types of unusual memory effect are detected. It is shown that the observed memory effects are due to pinning of the soliton superstructure by a defect density wave in the internal field of the electret state.