Phase transition and switching in lead titanate crystals

Abstract

Abstract Different phase-front shapes are described with respect to conditions of phase transition. An explanation of the origin of so-called reciprocal domains is proposed. These domains are shown to be stable against an effect of applied field. Phase transition behavior of lead titanate crystals is defined by i. A high conductivity near the Curie point, [sgrave] Tc ∼ 10−3 (ohm. cm)−1 (carrier concentration n ∼ 1018 cm−3); ii. phase-front conditions, i.e., a large elastic stress due to a change in unit-cell volume, VTC ∼ 0.3 A3, (c/a - 1)TC ∼ 0.012, with a large change in spontaneous polarization, Ps ∼ 40 μCI cm2 [l], and iii. conditions of phase transition, i.e., temperature-gradient direction with respect to crystal axes, (grad T)Tcmagnitude of temperature gradient and phase-front velocity. Consider the effect of these factors on the transition behavior, domain structure and switching process. Due to a high conductivity of lead titanate at the transition, the phase front is flat, which is characteristi...