Main content area

Lamellar and bundled domain rotations in barium titanate

Howell, Jane A., Vaudin, Mark D., Friedman, Lawrence H., Cook, Robert F.
Journal of materials science 2019 v.54 no.1 pp. 116-129
X-ray diffraction, barium titanate, crystals, models
Cross-correlation of electron backscatter diffraction patterns has been used to generate rotation maps of single crystals of tetragonal barium titanate (BaTiO₃) containing multiple lamellae and bundles of ≈ 90° domains. Rotation measurement angular resolutions of 0.1 mrad (0.006°) and spatial resolutions of 30 nm are demonstrated on structures with approximately 1 μm domains extending over 10s of μm. The material orientations demonstrated considerable microstructural dependence: c domains, with polarization perpendicular to a free surface, exhibited little within-domain rotation variation while a-domains, with polarization parallel to the surface, exhibited considerable within-domain variation, particularly in the larger lamellar domain structure. In both lamellar and bundled structures, the maximum a–c between-domain rotation was approximately equal to the value θᵣ ≈ 0.63° (11 mrad) predicted by a rigid rotation of tetragonal BaTiO₃ unit cells across the domain boundary. However, in both structures there was gradual variation in rotation throughout, especially adjacent to domain boundaries, suggesting that a rigid rotation model predicts too abrupt a unit cell and polarization rotation. A new BaTiO₃ compound defect was deduced through identification of a double integral surface rotation 2θᵣ. The double rotation is indicative of a low-angle grain boundary terminating at a surface by a confined 90° domain.