Crystal field modification via rare earth ions (Dy, Nd) incorporation on BiFeO3 fine nanoparticles

• Published in: Journal of materials science. Materials in electronics 2023-11, Vol.34 (31), p.2110, Article 2110
• Main Authors: Ben Taazayet, Wael, Mallek Zouari, Ikbel, Thabet Mliki, Najeh
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Dielectric properties; Electric properties; Information storage; Materials Science; Nanoparticles; Nitrates; Optical and Electronic Materials; Optical properties; Trace elements
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-023-11487-3

Rare earth (Dy, Nd)-doped and co-doped multiferroic bismuth ferrites nanoparticles (NPs) with formulas Bi 1 − x Dy x FeO 3 (x = 0, 0.02 and 0.04), Bi 1 −y Nd y FeO 3 (y = 0.02 and 0.04) and Bi 1− x −y Dy x Nd y FeO 3 ( x  = 0.02 and y = 0.02) were synthesized by a controlled hydrothermal process. X-ray diffraction (XRD) confirmed the presence of the typical rhombohedral distorted perovskite structure of BiFeO 3 (BFO) for all synthesized nanopowders. Whereas a slight impurity phase started to appear in both 4% Dy- and 4% Nd-doped BFO samples. The crystallite sizes as determined by Scherrer equation were found to increase slightly with doping. In close agreement, images seen by TEM confirmed the size of nanoparticles. EDX analysis confirmed the presence of elements in such sample. Optical study revealed a clear crystal field and band structure modification. Direct optical bandgap determined through Tauc plot deduced from reflectance measurement showed a remarkable decrease in value. The real and imaginary parts of dielectric constant ( ε ’, ε ”) show a maximum increase on co-doped BFO concomitant with remarkable increase in dielectric loss (tan δ ) which indicates substantial enlarge in leakage current density. Further, the pure BFO shows a well-defined dielectric loss peak, which shifts toward higher frequency for doped NPs. Vacancies proliferation is one of the main sources of movable space charges in BFO and, through, for leakage current.