Investigation of Sr-Doped BiFeO3 Synthesized by Sol–Gel Route

Abstract

The Sr-doped bismuth ferrite nanoparticles with chemical formula Bi_1–xSr_xFeO₃ (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared via facile sol–gel method. A detailed investigation was conducted into the effects of substituting divalent Sr²⁺ at the Bi³⁺ site on the structural, morphological, magnetic, and electrical characteristics. The XRD study revealed the occurrence of structural transformation in the samples upon doping. The reduction in crystallite size can be attributed to the creation of oxygen vacancies. The morphological analysis carried out using field emission scanning electron microscopy (FESEM) further validated this theory. The increasingly greater lattice distortion with doping is in line with the increasing value of microstrain for increasing doping concentrations. The improving stability of the structure with increasing doping concentration was confirmed by the increasing value of the tolerance (T) factor. The FESEM micrographs reveal the change in morphology of the particles upon doping. The EDS results confirm the expected presence of the constituent elements Sr, Bi, Fe, and O in permissible proportions. The M–H curve reported at 3 K and at ambient temperature both confirmed the appreciable increase in magnetization with increasing doping concentration. The investigation of the dielectric properties of the samples was performed using an LCR meter operating in the frequency range of 10 Hz–8 MHz. The results showed a marked increase in the value of the dielectric constant with an increase in doping concentration. The increasing resistivity of the doped BFO samples is confirmed by the significant values of grain resistance as indicated by the Cole-Cole plots. The good ferroelectric properties of the samples are revealed by the P–E loops and may find potential applications in spintronic devices and microwave devices. The P–E loops reveal the good ferroelectric nature of the samples and can have potential applications in spintronic devices and microwave devices.