EXAFS, X-ray diffraction and Raman studies of (Pb_1-xLa_x)(Zr_0.65Ti_0.35)O₃ (x = 0.04 and 0.09) ceramics irradiated by high-current pulsed electron beam

We report the effect of pulsed electron beam irradiation on the long-range and short-range atomic structure, as well as on the Raman phonon modes, of perovskite (Pb_1-xLa_x)(Zr_0.65Ti_0.35)O₃, x = 0.04 and 0.09 (PLZT 4/65/35 and 9/65/35) ferroelectric ceramics. X-ray powder diffraction (XRD) spectra from the single-pulse-irradiated PLZT 9/65/35 samples reveal transformation of the cubic Pm3m (Z = 1) into the orthorhombic Pmmm (Z = 1) structure. This symmetry change is however not observed for 10-pulse irradiation performed under the same conditions: here only an increase in the coherent scattering regions, lattice volume, and the Zr-O distance distribution is observed, as revealed by XRD and X-ray absorption spectroscopy at Zr K-edge. Raman scattering from PLZT 9/65/35 ceramics is in agreement with the symmetry reduction after single-pulse irradiation and reveals significant Raman signal intensity decrease after multiple-pulse irradiation. On the contrary, no significant structural changes could be detected in PLZT 4/65/35 ceramics after single- or multiple-pulse irradiation. Possible mechanisms of pulsed electron irradiation effects in PLZT 4/65/35 and 9/65/35 ceramics are discussed.