Mapping local defects in PbO-based piezoceramics

• Published in: Journal of crystal growth Vol. 317; no. 1; pp. 16 - 22
• Main Authors: Dimitriu, E., Ramer, R., Craciun, F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2011; Elsevier
• Subjects: A1. Crystal morphology; A1. Defects; A1. Point defects; Agglomeration; Annealing; B1. Perovskites; B2. Piezoelectric materials; Ceramics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystal defects; Defects and impurities in crystals; microstructure; Dielectric properties; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferroelectric materials; Ferroelectricity; Optical reflection; Physics; Point defects (vacancies, interstitials, color centers, etc.) and defect clusters; Structure of solids and liquids; crystallography; Titanium; B1. Perovskites; A1. Point defects; A1. Crystal morphology; A1. Defects; B2. Piezoelectric materials; Microprobe; Lead oxide; Electrical conductivity; Lead titanates; Piezoelectric properties; Gadolinium; XRD; Reflection spectrum; Impurity effect; Titanium; Defect structure; Crystal morphology; Optical reflection; Scanning electron microscopy; Annealing; Point defects; Dielectric properties; Manganese additions; Perovskites; Valence; Ferroelectric materials; Piezoelectric materials; Sintering; Microstructure; Energy-dispersive X-ray analysis; Manganese
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.11.029

The effect of impurities and defects of various types on the properties of ferroelectric perovskites remains a subject of great interest and is investigated by increasingly sophisticated experimental techniques. The microscopic structure and defect chemistry of ferroelectric lead titanate ceramics with complex compositions (doped with Mn, Pr, Nd and Gd) prepared by standard solid-state oxide method were investigated in this study. Phase formation and microstructure were examined by XRD and SEM, respectively. Grains with unusual shapes and sizes are observed in a homogeneous matrix. Agglomerations of chemical components randomly distributed in the samples are revealed using the energy dispersive X-ray analysis with the microprobe technique and the elemental distribution within bulk ceramics is profiled. At least two oxidation states of the titanium and manganese ions are evidenced from optical reflection spectra. All observed local defects in the ferroelectric ceramic depended on the composition, the sintering temperature and the annealing conditions, and affected the conductivity and the dielectric and piezoelectric properties.