Structural correlations of the enhancement of dielectric permittivity in the (Ta2O5)0.92(TiO2)0.08 system.

A Ti-ion ordering which correlates to the significant enhancement of the dielectric constant was determined in the (Ta2O5)0.92(TiO2)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 Ta2O5 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 (Ta2O5)0.92(TiO2)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. [ABSTRACT FROM AUTHOR]