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

de Queiroz TB, Mohr D, Eckert H, de Camargo ASS

Abstract

A new preparation route towards rare-earth (RE) doped polycrystalline lead lanthanum zirconate titanate (PLZT) ceramics (RE = Y3+, Nd3+, Yb3+), 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 207Pb 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 207Pb nuclei with the unpaired electron spin density results in significant broadening and shifting of the NMR signal, whereas these effects are absent in the diamagnetic Y3+ doped materials. Based on different concentration dependences of the NMR lineshape parameters, we conclude that the structural role of the Nd3+ dopants differs significantly from that of Yb3+. While the Nd3+ ions appear to be statistically distributed in the PLZT lattice, incorporation of Yb3+ into PLZT appears to be limited by the appearance of doped cubic zirconia as a secondary phase. © 2009 Elsevier Masson SAS. All rights reserved.