(217da) Crystallographic Changes in Lead Zirconate Titanate Due to High Neutron Radiation Exposure

Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation environments. However, such use requires knowledge of the structural response in the material to radiation exposure, and the nature of these changes is not currently known. Thus, the present work evaluates the change in the structure of a variety of technologically significant lead zirconate titanate (PZT) compositions. PZT based materials with a 50/50 zirconium to titanium ratio of the following three compositions were investigated: (1) undoped, (2) Fe-doped, and (3) Nb-doped PZT. Powder samples and disc shaped samples of all three compositions were synthesized using solid state processing. Laboratory X-Ray diffraction was used to determine the initial phase purity of the materials. Half of all the samples were exposed to a 1 MeV equivalent fluence of 1.7×10¹⁵ neutrons/cm² relative to the control group. After irradiation, neutron diffraction from the SMARTS diffractometer was used to analyze the crystal structures of each sample using Rietveld refinements. This approach allowed quantitative assessment of point defect concentrations. The refinements showed a mixture of the rhombohedral and tetragonal phases for these samples and most importantly showed that the oxygen and lead occupancies had measurably changed with irradiation.