The rhombohedral (R3c) unit cell of NBT. The lattice constant, angle, and the structural parameters are given in Table I .
(a) The total density of states of NBT. The partial density of states of NBT projected onto orbitals of (b) Ti atom, (c) Bi atom, (d) O atom, and (e) Na atom. Fermi energy is indicated by the dashed line.
Reitveld refined X-ray diffraction pattern of the sintered NBT sample with the inset showing the magnified lower angle region.
Room temperature P vs. E hysteresis loop and corresponding I-V curve of NBT sample.
Raman spectrum of NBT sample measured at 300 K. The overlapped bands (A-D) have been de-convoluted into their individual components as indicated by arrows after base-line correction.
Theoretical and experimental lattice constant ao (Å), angle α (in degrees), structural parameters (x,y,z), and volume Ω(Å3) of R3c NBT.
Fundamental frequencies (cm−1) of NBT with their symmetry assignments. Experimental data were taken at the room temperature.
Electronic and static dielectric tensors of NBT. The tensors are diagonal and have different components perpendicular ( ) and parallel (∥) to 3-fold  symmetry axis.
Components of mode effective charge vector ( ) and different mode contribution to static dielectric tensor perpendicular ( ) and parallel (||) to 3-fold  symmetry axis.
Article metrics loading...
Full text loading...