Structural and microstructural correlation with ferroelectric and dielectric properties of nanostructured Na^sub 0.5^Bi^sub 0.5^TiO3 ceramics

Issue Title: Special Issue: Electronic Materials for Harsh Environments Polycrystalline Na^sub 0.5^Bi^sub 0.5^TiO3 (NBT) ceramics were synthesized by using sol-gel and solid state reaction techniques with an average grain size of 240 nm and 14 [mu]m respectively. Structural analysis confirmed the R3c phase-stabilization in both bulk and nano-NBT. The lattice strain analysis estimated by using W-H plot from the XRD profiles revealed the strain was compressive in NBT-nano. Phonon life times (τ) of Na/Bi-O, Ti-O and TiO^sub 6^ phonon modes were decreased in NBT-nano due to the grain size effect. Microstructure of NBT-nano displayed an enormous rise in the number of grain boundaries than NBT-bulk. Ferroelectric loops became slanted in NBT-nano due to the multi-domain to mono-domain transformation. The mono-domain transition eased the domain reversal and switching, which in-turn lowered the E^sub c^ value in NBT-nano (i.e. E^sub c^ = 45 kV/cm). The clamping effect caused by grain size reduction in NBT-nano leads to reduced P^sub r^ value (P^sub r^ = 25.2 µC/cm^sup 2^). The compressive strain developed in the crystal lattice of NBT-nano leads to an increase in T^sub m^ (i.e. 335 °C). The variation in diffusivity parameter (γ) and degree of correlation strength q(T) between the polar nano regions were found to be the cause for enhanced relaxor features in NBT-nano.