Preparation and structural characterization of rare-earth doped lead lanthanum zirconate titanate ceramics

摘要

A new preparation route towards rare-earth (RE) doped polycrystalline lead lanthanum zirconate titanate (PLZT) ceramics (RE = Y~(3+), Nd~(3+), Yb~(3+)), based on the use of doped lanthanum oxide or zirconia, is reported. Structural characterization by X-ray powder diffraction reveals that secondary phase formation can be substantially diminished in comparison to conventional preparation methods. The distribution of the rare-earth dopants was investigated as a function of concentration by static ~(207)Pb spin echo NMR spectra, using Fourier Transformation of Carr-Purcell-Meiboom-Gill spin echo trains. For the Nd- and Yb-doped materials, the interaction of the ~(207)Pb nuclei with the unpaired electron spin density results in significant broadening and shifting of the NMR signal, whereas these effects are absent in the diamag-netic Y~(3+) doped materials. Based on different concentration dependences of the NMR lineshape parameters, we conclude that the structural role of the Nd~(3+) dopants differs significantly from that of Yb~(3+). While the Nd~(3+) ions appear to be statistically distributed in the PIZT lattice, incorporation of Yb~(3+) into PLZT appears to be limited by the appearance of doped cubic zirconia as a secondary phase.