Easy Synthesis of High-Purity BiFeO3 Nanoparticles: New Insights Derived from the Structural, Optical, and Magnetic Characterization
Por:
Ortiz-Quiñonez J.L., Díaz D., Zumeta-Dubé I., Arriola-Santamaría H., Betancourt I., Santiago-Jacinto P., Nava-Etzana N.
Publicada:
16 sep 2013
Resumen:
Synthesis of high-purity BiFeO3 is very important for practical
applications. This task has been very challenging for the scientific
community because nonstoichiometric BixFeyOz species typically appear as
byproducts in most of the synthesis routes. In the present work, we
outline the synthesis of BiFeO3 nanostructures by a combustion reaction,
employing tartaric acid or glycine as promoter. When glycine is used, a
porous BiFeO3 network composed of tightly assembled and sintered
nanocrystallites is obtained. The origin of high purity BiFeO3
nanomaterial as well as the formation of other byproducts is explained
on the basis of metal ligand interactions. Structural, morphological,
and optical analysis of the intermediate that preceded the formation of
porous BiFeO3 structures was accomplished. The thorough characterization
of BiFeO3 nanoparticles (NPs) included powder X-ray diffraction (XRD);
scanning electron microscopy (SEM) and high resolution transmission
electron microscopy (HRTEM); thermogravimetric analysis (TGA); UV-vis
electronic absorption (diffuse reflectance mode), Raman scattering,
Mossbauer, and electron paramagnetic resonance (EPR) spectroscopies; and
vibrating sample magnetometry (VSM). The byproducts like beta-Bi2O3 and
5 nm Bi2Fe4O9 NPs were obtained when tartaric acid was the promoter.
However, no such byproducts were formed using glycine in the synthesis
process. The average sizes of the crystallites for BiFeO3 were 26 and 23
nm, for tartaric acid and glycine promoters, respectively. Two band gap
energies, 2.27 and 1.66 eV, were found for BiFeO3 synthesized with
tartaric acid, obtained from Tauc's plots. A remarkable selective
enhancement in the intensity of the BiFeO3 A(1) mode, as a consequence
of the resonance Raman effect, was observed and discussed for the first
time in this work. For glycine-promoted BiFeO3 nanostructures, the
measured magnetization (M) value at 20 000 Oe (0.64 emu g(-1)) was
similar to 5 times lower than that obtained using tartaric acid. The
difference between the M values has been associated with the different
morphologies of the BiFeO3 nanostructures.
Filiaciones:
Univ Nacl Autonoma Mexico, Dept Quim Inorgan & Nucl, Fac Quim, Mexico City 04510, DF, Mexico
Univ Nacl Autonoma Mexico, Inst Invest Mat, Mexico City 04510, DF, Mexico
Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 04510, DF, Mexico
Instituto Mexicano Del Petróleo, Eje Central Lázaro Cárdenas Norte 152, San Bartolo-Atepehuacan, Madero, CP 077730, Mexico City, Mexico
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