Ferroelectricity in an Array of Electrically Coupled Confined Small Particles

Abstract

The influence of the pore network geometry and interparticle long-distance electric coupling on the ferroelectric phase transition in small particles embedded into mesoporous matrices is considered. It was shown that the temperature of the ferroelectric phase transition in a system of electrically linked particles can be well different from that in isolated small particles. In particular, the model suggests an explanation for the weakening of size-effects on the ferroelectric phase transition in confined geometry.

Phase transition in NH4HSO4–porous glasses nanocomposites

“…This remark is in agreement with the conclusion driven from the phenomenological model (Zhong et al 1994; Charnaya et al 2007). …”

“…The size dependence of the low-temperature phase transition temperature can be explained based on the phenomenological model (Zhong et al 1994; Charnaya et al 2007). According to (Zhong et al 1994), the phase transition temperature of the spherical particles with diameter d belonging to the cubic system can be described by equation:where T C∞ is the Curie–Weiss temperature of bulk crystals, D is connected with correlation length, Α is the Landau expansion coefficient, and δ ∞ is the extrapolation length.…”

Dielectric Studies of Thiourea, SС(NH2)2, Embedded into Molecular Sieves

“…However, for confined nanoparticles a strong impact of pore walls should be expected. Theoretical models also confirmed a noticeable influence of coupling between particles in adjoining pores on the shift of the ferroelectric phase transition [10,11]. The effect of the particular matrices on the phase transitions in confined particles was revealed for two most studied ferroelectrics: sodium nitrite and Rochelle salt [1,2,5,6,12,13].…”

Исследование фазовых переходов сегнетоэлектрика SС(NH-=SUB=-2-=/SUB=-)-=SUB=-2-=/SUB=- в нанопористых матрицах на основе Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

“…Отмечалось также влияние размеров частиц на спонтанную поляризацию и диэлек-трическую проницаемость. Многие из этих размерных эффектов можно объяснить в рамках теоретических моделей, развитых для полярных диэлектриков на ос-нове теории Ландау-Гинзбурга и Гинзбурга-Андерсона-Кохрена (см., например, [5][6][7][8]). Одним из способов по-лучения малых сегнетоэлектрических частиц является внедрение сегнетоактивных материалов в нанопористые матрицы [9].…”