Author : Abhishek Kumar, Ram Kumar, Beauty Kumari, Ankit Kumar, Sandeep Kumar Jha and K. Prasad

Perovskite ABO₃ materials have garnered significant attention due to their potential for electronic and microelectronic applications. Lead-based compounds, such as PbTiO₃, Pb(Zr,Ti)O₃, and Pb(Mg₁/₃Nb₂/₃)O₃, are widely utilized but pose environmental risks, prompting a search for lead-free alternatives. To this end, morphotropic phase boundary composition of Ba-modified (Bi0.5Na0.5)TiO3 is considered to be a promising candidate Ba₀.₀₆(Bi,Na)₀.₉₄TiO₃, which shows promising dielectric and piezoelectric properties. In order to further enhance the dielectric characteristics of Ba₀.₀₆(Bi,Na)₀.₉₄TiO₃, the Ti⁴⁺-ions have been substituted with the pseudo-cation (𝑁𝑖13/+3𝑁𝑏25/+3)4+. Accordingly, in this study, lead-free solid solutions of (1-ϕ)Ba₀.₀₆Na₀.₄₇Bi₀.₄₇TiO₃–ϕBa₀.₀₆Na₀.₄₇Bi₀.₄₇(Ni₁/₃Nb₂/₃)O₃ (0 ≤ ϕ ≤ 1.0) have been synthesized using the solid-state reaction process. Also, the real and imaginary components of permittivity at 1 kHz were analysed as functions of filler (Ba₀.₀₆Na₀.₄₇Bi₀.₄₇(Ni₁/₃Nb₂/₃)O₃) concentration. The suitability of dielectric mixture equations, including Bruggeman, Furukawa, Rother-Lichtenecker, modified RotherLichtenecker, and Knott models, was evaluated. Additionally, a first-order exponential growth model provided an excellent fit to the data (r² > 0.99).

Keywords: Lead free, Solid solution, Complex permittivity, Dielectric mixture equations, Dielectric loss