Correlation between structural, ferroelectric and luminescence properties through compositional dependence of Nd3+ ion in lead free Na0.5Bi0.5TiO3

Highlights: • The evolution of intermediate O- phase with the substitution of ${\text{Nd}}^{3+}$ in lead-free $\text{NBT}$ through the structural refinement. • The induced relaxor feature with substitution of Nd as confirmed from bipolar strain measurements. • The effect of induced structural transformation is reflected in the polarization and photoluminescence measurements. • The suppression of luminescence due to higher symmetric structure is explained with the help of Judd-Oflet theory. We present a comprehensive investigation on the dependence of Nd³⁺ substitution on various properties in $\left[N{a}_{0.5}B{i}_{0.5-x}N{d}_x\right]Ti{O}_3$ (NBNT) for $x=0-0.1$. The structural analysis of XRD measurements revealed a crossover structural phase transition from monoclinic ($Cc$) to orthorhombic ($Pbnm$) for composition $\text{s}0.04\le x\le 0.1$. Increase in Nd³⁺ substitution resulted in larger grain size. Enhanced electrical properties were observed for $x=\mathrm{0.01.}$ Dielectric measurements revealed the relaxor behaviour enhances with the content of Nd³⁺, which is verified with help of bipolar strain loops. The polarization measurements support the evolution of centrosymmetry space group over particular cross over for NBNT with $x=0.04$. In concomitance with enhanced electrical properties, the luminescence measurements showed the largest emission for $x=0.01$ for the Nd³⁺ substituted NBT. The onset of luminescence quenching starts from the substitution of $x=0.03$ which can be surmised to be due to the effect of centro-symmetric ($Pbnm$) of orthorhombic structure in addition to the expected concentration quenching effects. The results presented here, establishes the substitution of Nd³⁺ into the NBT resulted in enhanced electrical and optical properties compared to parent NBT, making these NBNTs promising candidate for multifunctionality applications.