Size-dependence of Magnetic Properties of Bismuth Ferrite Nanopowders

Abstract

A series of BiFeO3 nanopowders were prepared by the sol-gel process. X-ray diffraction analysis shows that their rhombohedral crystal symmetry remains unchanged. However, as the particle size decreases, the edge length of the unit cell increases markedly and the angle between the edges deviates increasingly from 60°. Magnetic measurements show obvious weak ferromagnetism. The magnetization and magnetic susceptibility increase with decreasing particle size. Mössbauer studies reveal that the spin canting angles in the smaller particles are bigger and have a wider distribution. The magnetic structure in these particles is a complicated uncompensated antiferromagnetic spin arrangement.

Synthesis of classes of ternary metal oxide nanostructures

“…To address this problem, recent approaches have focused on developing novel structures of BiFeO 3 . [121][122][123][124] For instance, BiFeO 3 nanoparticles, with average sizes of 21 to 59 nm, were prepared from precursor materials including Bi 2 O 3 , Fe(NO 3 ) 3 ?9H 2 O, citric acid, and a dispersion agent in diluted nitric acid. 122 Preliminary magnetic property measurements of these nanoparticles were performed, showing enhanced properties corresponding to reduction of size, an effect discussed on the basis of Mo ¨ssbauer results.…”

“…[121][122][123][124] For instance, BiFeO 3 nanoparticles, with average sizes of 21 to 59 nm, were prepared from precursor materials including Bi 2 O 3 , Fe(NO 3 ) 3 ?9H 2 O, citric acid, and a dispersion agent in diluted nitric acid. 122 Preliminary magnetic property measurements of these nanoparticles were performed, showing enhanced properties corresponding to reduction of size, an effect discussed on the basis of Mo ¨ssbauer results. Very recently, the preparation of nanosized bismuth ferrites from Bi(NO 3 ) 3 and Fe(NO 3 ) 3 precursors with tartaric acid in nitric acid was reported; particle sizes obtained were in the range of 3 to 16 nm.…”

Synthesis and characterization of multiferroic BiFeO3 nanotubes

“…Preliminary magnetic property measurements of these nanoparticles were performed, showing enhanced properties corresponding to reduction of size. 12 To our knowledge, there have not been any viable syntheses of 1D nanostructures of BiFeO 3 reported. The fabrication of 1D nanostructures of BiFeO 3 is of fundamental importance in investigating size correlation of the basic physical properties of these materials, with implications for their device applications.…”

“…To address this problem, recent approaches have focused on developing novel structures of BiFeO 3 . 7,12 For instance, thin films of BiFeO 3 show physical properties such as spontaneous polarization, saturation magnetization, and a piezoelectric response, that are significantly enhanced relative to that of the bulk. 7 In addition, BiFeO 3 nanoparticles have been synthesized by a sol-gel process using organic precursors in the presence of dilute nitric acid solution.…”

Rapid Synthesis of Multiferroic BiFeO3 Single-Crystalline Nanostructures

“…Much effort has been made to understand the dependence of physical and chemical properties of the ternary transitional metal oxides, such as BaTiO 3 , PbTiO 3 , and SrTiO 3 , on the size and shape of the crystals in the material. , The synthesis method used to obtain the desired nanostructures is crucial for exploiting nanoscale electric, magnetic, and thermal properties. For the multiferroic material BiFeO 3 , however, the limitedly available information relating to the size dependence of the physical properties is mainly due to the difficulty in preparing the pure BiFeO 3 . During the synthesis of BiFeO 3 , the kinetics of phase formation in the Bi 2 O 3 −Fe 2 O 3 system can easily lead to the appearance of impurity phases, such as Bi 25 FeO 40 and Bi 2 Fe 4 O 9 . − Generally, BiFeO 3 can be obtained with the help of leaching out the impurities by the diluted nitric acid. , Most recently, it was realized in the synthesis of pure BiFeO 3 ceramics by a rapid thermal technique .…”