Structure of Thin Pseudo-90° Domain Walls in BaTiO₃

Abstract

The model of thin 90 • ferroelectric domain walls with first-order phase transition into induced phase is proposed. Crystallographic parameters, symmetry of a layer, surface density of elastic energy of a domain wall are determined. It is shown, that in tetragonal phase BaTiO 3 formation 12 orientation states and 24 electric domains is possible.

Evolution of ferroelectric domain structures embedded inside polycrystalline BaTiO3 during heating

“…Furthermore, the relative positions of the spots as a function of temperature mimic the changes in the lattice parameters as a function of temperature. These observations suggest that the four different spots correspond to four unique domain orientations in a tetragonal perovskite crystal, a result which will be shown to be consistent with the expected domain wall orientations in this symmetry [26][27] .…”

“…From the calculated misorientation angle between the orientations of the domain variants and the orientation of the grain with spot E shown in Table 1, none of the domains have an orientation that precisely equals that of the paraelectric cubic state. Nepochatenko 27 has shown that the domains can rotate a small angle during the cubic-to-tetragonal phase transformation to maintain the strain compatibility as a function of changing lattice aspect ratio. This rotation is relative to the sample coordinate axes and represents a rotation of the entire domain crystal axes; such a rotation is not the same as a polarization rotation involving crystallographic distortions as described in Ref.…”

“…that represent the lattice parameters for cubic phase (a 0 ) change to tetragonal (a, c). These angles are required for strain compatibility between the domain and the paraelectric phase 26,27 . The phase matching angle is calculated in the present work to be 0.28°±0.03° from the major axes between the orientation of the ferroelectric domains at room temperature and the high temperature paraelectric cubic state.…”

Determination of Functional Dependence Between Parameters of Lattice in Ferroelastics and Multiaxial Ferroelectrics

“…As a layer of the induced phase of pseudo-90 • domain wall does not contain a shear deformation [7], the condition of orientation matching of domains is satisfied, if G si = G wi and consequently, equations (2) and (3) must be equal. Therefore…”

“…It is obtained from the model of this domain wall, which equation in CS of ferrophase depends on the ratio of lattice parameter values [7]:…”