Influence of Depolarizing Fields and Screening Effects on Phase Transitions in Ferroelectric Composites

Abstract

The temperature of the transition to the polar state in ferroelectric composites, representing spherical ferroelectric inclusions embedded in a dielectric matrix, under a depolarizing field effect is investigated. This temperature is determined both in the absence and presence of screening effects of the depolarizing field of the bound charges of spontaneous polarization at the inclusions surface. The absence case shows that the Curie point shift is determined by the ratio of the Curie constant of the ferroelectric inclusion to the permittivity of the matrix. Screening effects show that the transition temperature shift decreases through multiplying the value by a decreasing factor equal to the ratio of the screening length to the radius of the ferroelectric inclusion. Examples of the materials for the position of the Curie point on the temperature scale, largely determined by the tilting action of the depolarizing field and the compensating shielding effects, are given.

Dielectric and Thermal Properties of KNO3 Encapsulated in Carbon Nanotubes

“…The phase transition temperatures in ferroelectric particles will be determined from the minimum condition for the free energy of particle taking into account the interaction, (3) As shown in [19], the consideration of the interaction of polar particles with matrix leads to a decrease in the phase transition temperature, equal to the ratio of…”

Диэлектрические И Тепловые Свойства KNO-=SUB=-3-=/SUB=-, Внедренного В Углеродные Нанотрубки

“…Как было показано в [19], учет взаимодействия полярных частиц с матрицей приводит к понижению температуры фазового перехода, равному отношению постоянной Кюри−Вейса C включений к диэлектрической проницаемости матрицы ε:…”

Analytical solution of orthogonal similar oblate spheroidal coordinate system

“…In electrostatics and solid state physics, the SOS coordinates could find application in description of electric field potential in ferroelectric materials (e.g. ferroelectric nanocomposites) containing dielectric inclusions (or vice versaferroelectric inclusions in dielectric matrix) [7], particularly the inclusions of spheroidal shape [8].…”