The theoretical model for the ferroelectric effect in barium titanate (Mason and Matthias, 1948) assumes a displacement of the titanium from the center of the unit cell in the z direction, probably due to the formation of a covalent bond with the c-centered oxygen. This displacement had been observed earlier by Dr. Danielson (Danielson, Matthias, and Richardson, 1948) and given as about 0.16A, at 20°C. This value, based on the relatively high intensity of x-ray scattering from the 0-0-11 plane, as shown by a Weissenberg pattern using molybdenum radiation was later brought into question by work at the Institute for Atomic Research (Danielson and Rundle, 1949), using silver radiation.
Proceedings of the Iowa Academy of Science
©1950 Iowa Academy of Science, Inc.
Grimsal, Edward G.
"Structure of BaTiO3,"
Proceedings of the Iowa Academy of Science, 57(1), 331-336.
Available at: https://scholarworks.uni.edu/pias/vol57/iss1/42