Daihong Kuang

Effects of Pr and Ni Co-Substitution on the Structural and Ferroelectric Properties of BiFeO3 Thin Films Prepared by a Sol-Gel Method

BiFeO3 (BFO) and Bi0.9Pr0.1Fe1-xNixO3 (0.01 ≤ x ≤ 0.1) thin films have been fabricated on Pt(111)/Ti/SiO2/Si substrates by a sol-gel method. The Pr and Ni co-substitution effects on the structural and ferroelectric properties of BFO films were investigated by X-ray diffraction (XRD), Raman spectroscopy and ferroelectric measurements. XRD and Raman analysis demonstrated that all films have a pure phase related to perovskite-type structure. The ferroelectric test indicated that the ferroelectric properties of BFO films were improved with Pr and Ni co-doping. The remnant polarization of Bi0.9Pr0.1Fe0.95Ni0.05O3 film was 70 μC/cm2. The leakage current density-applied electric field behavior measurement showed that Pr and Ni co-substitution was effective to reduce the leakage current density of BFO thin films.

Preparation and enhanced ferromagnetic properties in Co doped BiFeO3 nanoparticles prepared by sol–gel method

ABSTRACT BiFe1-xCoxO3 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25) nanoparticles were prepared by a sol–gel method. A single-phase perovskite structure was formed in the pure BiFeO3 particles. The secondary phase of Bi25FeO40 was observed in Co doped samples and the phases of CoFe2O4 were observed in BiFe0.8Co0.2O3 and BiFe0.75Co0.25O3. The average crystal size of pure BiFeO3 is about 84 nm and that was reduced from 84 nm to 49.7 nm with increasing Co content. Optical band gaps of BFCO nanoparticles decrease with the increase of Co concentration. The enhancement of room-temperature ferromagnetism was obtained in the Co doped BiFeO3 particles.

The Structural and Magnetic Properties of Bi1-xYxFe1-yMnyO3 Particles Synthesized Via a Sol-Gel Technique

Bi1-xYxFe1-yMnyO3 (BYFMO, x = 0, 0.1; y = 0, 0.05, 0.1, 0.15, 0.2, 0.25) particles were prepared via a sol-gel technique. The structural, morphological, optical, and ferromagnetic properties of the as-prepared BYFMO samples were analyzed. The crystal structures of all samples except Bi0.9Y0.1FeO3 (contain a small amount of Bi25FeO40) were single-phase and crystallize in a rhombohedral structure (space group, R-3c). All 13 active modes were observed in the Raman spectra of pure BFO, which further confirmed its rhombohedral structure. Ferromagnetic properties and enhanced magnetic were observed inBi0.9Y0.1Fe0.9Mn0.1O3 particlesand other Y-Mn co-doped particles, respectively.