Microstructure and ionic conductivity of (La1/2Li1/3+ x )TiO3 perovskite-like solid solutions.

The lattice parameters of (La_1/2Li_{1/3+ x} )TiO₃ ( x = 0, 1/10, 1/6, 1/5, 1/4) ceramics have been determined as functions of temperature, and their microstructure and transport properties have been studied. The results indicate that the oxides retain orthorhombic symmetry upon the structural changes at ≃925 K. According to atomic force microscopy results, the grains in the ceramics consist of nanocrystallites 60 to 120 nm in size. Analysis of the grain bulk and grain boundary contributions to the ionic conductivity of the (La_1/2Li_{1/3+ x} )TiO₃ solid solutions shows that their bulk conductivity σ_bulk decreases with increasing x because reducing the concentration of A-site vacancies impedes ionic transport. [ABSTRACT FROM AUTHOR]