Manifestation of interaction of incommensurate modulated structure with defects in the birefringence properties of (N(CH₃)₄)₂FeCl₄crystals

Behaviour of the Optical Birefringence in Conditions of the "Viscous" Interaction

“…Their shape vIew has been discussed in different works [3,4]. Moreover, the magnitude of δ(Δn) anomalies is considerably changed depending from the investigated crystal [5][6][7] and the sample of the same crystal [8]. In accordance with Refs.…”

“…The [Ν(CH 3 ) 4 ] 2 CuCl 4 crystal was chosen as an object of investigation, because it does not possess ferroelectric properties and also the anomalies of δ(Δn) in the form of "splashes" at "viscous" interaction [20] have been observed at a rather high rate of temperature change δΤ/δt = 240 mK/h [21].…”

Characteristic Features of the Modulated Phases in (MgGeF6)·6H2O Crystals

“…6 one can define the six temperatures (T 1 = 316.1, T 2 = 316.34, T 3 = 317, T 4 = 318.14, T 5 = 318.38, T 6 = 319.82 K) of such transitions. According to [7] under the influence of the external stresses (electric or mechanical fields) the temperature range of the metastable states ex-istence changes, otherwise the region of commensurate phases existence changes too. To confirm the existence of such regions in the vicinity of T c the mechanical stress was applied to the sample.…”

Influence of Mechanical Stress on the Birefringence Properties of (N(CH3)4)2ZnCl4Crystals

“…Then the δ(Δn)c f(F) dependence is characterized by a sequence of peaks which are similar to the ones in the temperature dependence δ(Δn)i = f(T) at a low rate of temperature changes (∂Τ/'∂ t = 6 0 m K / h ) [ 6 ] . T h e s o -c a l l e d " v i s c o u s " i n t e r a c t i o n manifests itself if the velocities of the IC-stucture motion and defect diffusion become close and the optimum conditions for soliton-defect interaction arise [6]. The force-velocity dependence describing soliton motion [7] acquires a hysteresis character at "viscous" interaction.…”