Orientation, stress, and strain in an (001) barium titanate single crystal with 90° lamellar domains determined using electron backscatter diffraction

The orientation, stress, and strain in a single crystal of barium titanate (BaTiO₃), containing relatively large (0.5–14.5 μm), parallel, lamellar domains, have been determined and mapped using electron backscatter diffraction (EBSD). The strain distribution in the single crystal was determined using cross-correlation analysis of the EBSD patterns. Strain in the (001) single crystal was dominated by strain in the minority a-domain bands with peak values of −0.006 determined in the surface plane, perpendicular to the intersection of the domain walls with the crystal surface, compared to +0.002 in the same direction for the majority c-domains. The out-of-plane strains were negatively correlated with the in-plane strains and were about a factor of two smaller. The experimentally determined strains peak at domain boundaries and suggest a contraction of the c-axis and an expansion of one of the a-axes as the domain wall is approached. The ratios of the in-plane and out-of-plane strains were consistent with the bulk elastic constants of BaTiO₃. Stress values determined from the strains and the elastic constants peaked at 400 MPa.