Influence of the crystal microstructure on the dielectric response of the La_(0.67)Li_(0.2)Ti_(0.8)Al_(0.2)O_3

摘要

Polycrystalline samples of La_(0.67)Li_(0.2)Ti_(0.8)Al_(0.2) with different crystal microstructures have similar general dielectric behavior. The materials show very high dielectric permittivity (ε′ ≈ 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.