Dielectric properties of Bi-doped Ba0.8Sr0.2TiO3 ceramic solid solutions

Bismuth-doped barium-strontium-titanate ceramics of the formula (Ba0.8Sr0.2)(1−1.5y)BiyTiO3 were prepared using a conventional solid-state reaction method. The structure, dielectric properties, and ferroelectric relaxor behaviour of all compositions were thoroughly investigated. The findings revealed a broad dielectric anomaly and a shift in dielectric maxima towards higher temperatures with increasing frequency. The diffuseness degree indicator γ was about 1.68, and dielectric relaxation was noted to follow the Vogel-Fulcher relationship, with Tf=185 K, f0=1.18×1010 Hz, and Ea=0.35 eV, which further supported the spin-glass-like properties of BBSTs. The latter were also noted to display significant ferroelectric relaxor behaviour that could be attributed to the presence of Bi3+ doping ions. The degree of relaxation behaviour was noted to increase with the increase in bismuth concentration. Raman spectra were investigated as a function of temperature, and the findings confirmed the results from X-ray and dielectric measurements. Among the compositions assayed in this solid solution, 10% Bi-doped Ba0.8Sr0.2TiO3 yielded promising relaxor properties that make it a strong candidate for future industrial application in the production of efficient and eco-friendly relaxor ferroelectric materials.