Influence of the crystal microstructure on the dielectric response of the La0.67Li0.2Ti0.8Al0.2O3.

Polycrystalline samples of La0.67Li0.2Ti0.8Al0.2 with different crystal microstructures have similar general dielectric behavior. The materials show very high dielectric permittivity ([variant_greek_epsilon]′≈300 000) over relatively wide frequency and temperature ranges with no apparent dependence on the microstructure. The impedance spectroscopy study indicates that the origin of the high dielectric constant is a barrier layer capacitor effect due to depletion of Li ions at the grain boundaries of these Li-conducting materials. However, influence of the three dimensional microstructure domains on bulk properties such as electrical resistance and capacitance is observed. [ABSTRACT FROM AUTHOR]