Reconciling the apparently contradictory results of NMR and x-ray absorption fine structure measurements on the ferroelectric perovskite $\mathrm{B}\mathrm{a}\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{3}}$ gives insight into the character of the displacive and order-disorder components of the phase transitions of this material. The order-disorder component in the transition consists of local atomic displacements from cubic symmetry of constant magnitude that partially lose long-range order, while the displacive component consists of reorientation of these displacements.

• Received 23 September 2003

DOI:https://doi.org/10.1103/PhysRevLett.93.037601