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DF: Fachverband Dielektrische Festkörper

DF 4: Multiferroics, Phase Transitions & Relaxors

DF 4.4: Talk

Monday, March 23, 2009, 11:20–11:40, WIL B321

Effect of Ru doping on the structure and properties of PbZn_1/3Nb_2/3O₃-PbTiO₃ near the morphotropic phase boundary — Torben Scholz¹, •Boriana Mihailova², Gerold A. Schneider¹, Nils Pagels³, Jürgen Heck³, Marin Gospodinov⁴, and Ulrich Bismayer² — ¹Institute of Advanced Ceramics, Hamburg University of Technology — ²Institute of Mineralogy and Petrology, University of Hamburg — ³Institute of Inorganic and Applied Chemistry, University of Hamburg — ⁴Institute of Solid State Physics, Bulgarian Academy of Sciences

The search for novel multifunctional materials has spotted Pb-based perovskite-type solid solutions of relaxor and normal ferroelectrics because of their huge electromechanical coupling and strong photoelastic effects near the morphotropic phase boundary. We studied the local atomic structure, domain pattern and properties of pure and Ru-doped 0.9PbZn_1/3Nb_2/3O₃-0.1PbTiO₃ single crystals by applying atomic and piezoresponse force microscopy (AFM/PFM), dielectric measurements, X-ray diffraction analysis, Raman scattering and electron paramagnetic resonance. AFM/PFM images reveal the existence of tetragonal and non-tetragonal ferroelectric domains in 0.9PZN-0.1PT. The dielectric and elastoelectric loops show that Ru doping, Ru/(Ti+Zn+Nb) = 0.002, leads to significant ferroelectric hardening due to the immobilization of domain walls. Besides, the addition of Ru decreases the ferroelectric domain size, reduces the polar fraction distributed in the pseudo cubic matrix and changes the unit cell parameters of the overall tetragonal structure.