Optical and dielectric properties of Nd and Sm-doped Bi₅Ti₃FeO₁₅

Rare earth-doping of bismuth titanates is one of the main strategies to improve their optoelectronic properties, as it is useful for several types of application. In this context, this work aimed to produce a samarium and neodymium-doped Bi₅Ti₃FeO₁₅ compound and evaluate the impacts of doping on its optical and electrical responses. Thus, the materials were produced by a solid state reaction and characterized by X-ray diffraction, Raman scattering, infrared absorption, X-ray fluorescence, scanning electron microscopy, impedance spectroscopy and diffuse reflectance spectroscopy. The results revealed that doping was successfully attained with no detectable secondary phase. Site specific substitution was observed for both dopants, in a typical Aurivillius-layered structure. The samples demonstrated high electrical resistance and both dopants actuated positively for the material's dielectric performance. However, samarium displayed the best results for dielectric application, taking into account the increment of enthalpy for defects motion and higher dielectric permittivity. On the other hand, the evaluation of optical properties demonstrated that neodymium had bands of radiation absorption at visible and near-infrared spectra, which can be useful for devices such as selective optical detectors. Therefore, these results corroborate with the potentiality of rare earth doping for modifying the properties of bismuth iron titanates for specific optoelectronic applications.