Structural correlations of the enhancement of dielectric permittivity in the (Ta_2O_5)_(0.92)(TiO_2)_(0.08) system

摘要

A Ti-ion ordering which correlates to the significant enhancement of the dielectric constant was determined in the (Ta_2O_5)_(0.92)(TiO_2)_(0.08) system by high resolution electron microscopy and the corresponding simulations. The alien Ti ions were determined to selectively sit on the octahedral locations in the Ta_2O_5 base structure in an average of 9-time period along the (110) direction. The authors suggest this Ti-ion ordering induces the directional enhancement of the dielectric permittivity of the (Ta_2O_5)_(0.92)(TiO_2)_(0.08) system. The atomic mechanism of this modulated structure contributing to the enhancement of the dielectric constant was qualitatively interpreted using a one-dimensional chain model. The structural correlations of the dielectric enhancement revealed in this study suggest a way to search or design high-k materials.