Influence of A-Site Ag Substitution on Structural and Electrical Properties of Bi_1/2Na_1/2-xAg_xTiO₃ (x = 0.0, 0.025, 0.075, and 0.1) Lead-Free Ceramics

Silver-doped Bi_1/2Na_1/2-xAg_xTiO₃ (BNAT) ceramics (x = 0.0, 0.025, 0.075, and 0.1) were synthesized using the solid-state reaction (SSR) technique. The structural analysis was performed using the X-ray diffraction (XRD) technique, which revealed the formation of a polycrystalline sample with R3c symmetry. Pristine Bi_0.5Na_0.5TiO₃ (BNT) ceramics exhibited an average crystallite size of ~25.372 nm. Doping a small amount of Ag⁺ ions in place of Na⁺ ions resulted in an improved average crystallite size of ~26.365 nm, as calculated by Debye-Scherrer’s formula. Raman spectra were employed to investigate the vibrational modes of the materials. The FTIR spectra of Ag⁺-doped BNT ceramics displayed two strong peaks at ~971 and 537 cm⁻¹, attributed to the presence of metal-oxygen bonds. Room temperature dielectric constant (ε′) and dielectric loss (tan δ) analyses were conducted in the frequency range of 20 Hz to 1 MHz. Complex impedance and modulus spectroscopic analyses indicated the presence of grain boundary effects alongside the bulk contribution and also confirmed the presence of non-Debye relaxations in the materials.