Re-examination of the antiferroelectric structure of PbZrO3

The crystal structure of antiferroelectric PbZrO3 was re-examined by high resolution powder neutron diffraction. The structure obtained with assumed modulations associated with the lattice vibrational modes Sigma(3)(TO) and R-25(xy) is almost the same as that obtained previously with the same assumptions. However, one coordinate of oxygen positions obtained by the refinement for all crystallographically possible parameters is different from that obtained previously under the same conditions. The difference between the two sets of the structural parameters obtained here is meaningful. The result indicates that the modulation associated with the R-25(xy) mode is fairly distorted. This structure agrees well with that recently investigated using local-density calculations.