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Ln 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 (Ln=La, Pr, Nd, Sm) perovskite-type complex oxides were synthesized using a glycine-nitrate process, and the structure, electrical conducting and thermal expansion properties of the resulting ceramics were examined with regard to the nature of the lanthanide cations. The results indicated that the La, Pr and Nd specimens had a rhombohedral symmetry, while an orthorhombic structure was determined for the Sm specimen. The pseudo-cubic lattice constant decreased with smaller lanthanide cations. It was found that the electrical conducting properties declined with decreasing lanthanide cation size. Fortunately, all the compositions remained rather high electrical conductivities exceeding 650 Ω -1 ·cm -1 in the intermediate temperature range (600-800 ℃). An appreciable thermal expansion increase at high temperatures was detected for all the compositions. Decreasing the size of the lanthanide cations resulted in an increase of thermal expansion. With respect to the high electrical conductivities, the Ln 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 oxides are considered to be acceptable as mixed conducting component in composite cathode designs together with doped ceria electrolytes.

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The structure and electrical properties of (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 ceramic. It was ascertained that the MnO addition did not cause remarkable change in crystal structure and microstructure. The MnO addition mainly displayed a hard effect on the electrical properties, an increase of coercive fi eld (E c ) and mechanical quality factor (Q m ) together with a decrease of dielectric constant (ε r ) and piezoelectric constant (d 33 ). An enhancement of electromechanical coupling factor (k p ) with the MnO addition was obtained too. An essential relation between the piezoelectric properties and ferroelectric nature of the ceramics was detected. It was found that the piezoelectric properties of the ceramics highly depended on the corporative contribution of remanent polarization (P r ) and coercive fi eld.