Observation of a new memory effect in a modulated structure

Abstract

We report the first observation of a new memory effect in a modulated structure (deuterated thiourea). We present a qualitative explanation of this effect in terms of mobile defects, or impurities, interacting with the modulation order parameter. We show that this effect can be used to obtain the lines of constant modulation wavevector in the E, T plane of the phase diagram, by thermodynamic methods. We suggest that a similar periodic modulation of defect concentration occurs in CDW systems, like NbSe 3, and accounts for the non linearity induced by the electric field. (CDW : Charge Density Wave.