Synthesis, characterization, and dielectric properties of Y-doped strontium bismuth niobate (SrBi2−xYxNb2O9) ceramics: a lead-free ferroelectric alternative with enhanced performance

The scientific research findings emphasize the need to replace lead-based ferroelectric ceramics with environmentally friendly alternatives, driving heightened research interest in materials rivaling the performance of lead zirconate titanate (PZT). Among potential substitutes, bismuth layered structure ferroelectrics (BLSF), or Aurivillius compounds, have gained prominence. Our focus is on synthesizing Y-doped strontium bismuth niobate (SrBi2−xYxNb2O9), a BLSF material. Employing the solid-state treatment method, the structural, electrical, and dielectric properties of undoped and doped ceramics were scrutinized. Characterization involved X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Dielectric properties were systematically evaluated across frequencies and temperatures. XRD revealed the formation of the pure phase structure SrBi2Nb2O9 at 1100 °C, with no secondary phases. FTIR exhibited characteristic bands at approximately 619 cm−1 and 810 cm−1. SEM displayed thin plate-like grains and crystallites (sizes < 1 nm and 24 nm, respectively). The SrBi2−xYxNb2O9 ceramic demonstrated low dielectric loss values. Yttrium substitution for bismuth notably shifted the ferroelectric–paraelectric transition temperature from 460 to 435 °C, influencing dielectric constant behavior at higher frequencies. Structural and property changes were attributed to physicochemical phenomena, elucidated by considering density and lattice parameters.