Grain boundary mobility of BaTiO3 doped with aliovalent cations

• Published in: Journal of the European Ceramic Society Vol. 18; no. 8; pp. 1063 - 1071
• Main Authors: RAHAMAN, M. N, MANALERT, R
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01.01.1998
• Subjects: Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Exact sciences and technology; Grain and twin boundaries; Physics; Structure of solids and liquids; crystallography; Grain size; Grain boundaries; Inorganic compounds; Barium titanate; Impurity density; Ternary compounds; Doping; Grain boundary migration; Experimental study; Oxide ceramics; Lanthanum additions; Niobium additions; Cobalt additions; Kinetics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/S0955-2219(97)00215-X

The effect of three aliovalent cations, Nb5+, La3+ and Co2+, on the grain growth kinetics of nearly fully dense BaTiO3 (Ba/Ti atomic ratio = 1.001) was measured in O2 at 1300 C and for dopant concentrations of up to 1.25 at%. For the donor cation Nb5+, the boundary mobility initially increased with cation concentration but then decreased markedly above a doping threshold of 0.3-0.5 at%. The boundary mobility of the BaTiO3 doped with the acceptor cation Co2+ decreased monotonically with dopant concentration. At a cation concentration of 0.75 at%, the boundary mobility was reduced by a factor of approximately 25, 10 and 50 times by Nb5+, La3+ and Co2+, respectively. A major role of the dopants is seen to be their ability to influence the boundary mobility. The effects of the dopants on the boundary mobility are discussed in terms of the defect chemistry and the space-charge concept. 28 refs.