Papers by Keyword: BaTiO₃ Nanoparticles

Abstract: Nanocomposite in the form of a porous matrix SiO₂ with average pore size of 320 nm filled with barium titanate nanoparticles in paraelectric cubic phase was obtained. Shift of the stretching vibration of Si–O–Si to higher frequencies caused by increased strengthening of the network in the matrices has been observed. Also demonstrated that decrease in the intensity of the absorption relating to Si–O(H) stretching vibration relative to Si-O(−Si) stretching vibration. Raman scattering spectra demonstrate the presence of both a cubic and a tetragonal ferroelectric crystalline phase in the filler nanoparticles. Thus, the mechanical deformation of nanoparticles in the pores of the matrix can lead to a change in the crystalline phase of the filler.

Abstract: The suspension stability was investigated as the function of particle number concentration, applied force, and the distance between cathode and anode. The suspension was prepared by using BaTiO3 nanoparticles in a mixed solution with ethanol and acetylacetone. The highest zeta potential value was 30 mV, when the mixing ratio of EtOH and Acac was 75 : 25. EPD conditions of BaTiO3 nanoparticles suspension with 0.05 wt% were settled at the conditions of an applied dc field of 20 V/
and an electrode distance of 1.5
at 300 seconds of deposition time.

Abstract: BaTiO3 (BT) nanoparticles were prepared by the hydrothermal technique using different starting materials and the microstructure examined by XRD, SEM, TEM and HRTEM. X-ray diffraction and electron diffraction patterns showed that the nanoparticles were the cubic BaTiO3 phase. The BT nanoparticles prepared from the starting materials of as-prepared titanium hydroxide and barium hydroxide have spherical grain morphology, an average size of 65 nm and a fairly narrow size distribution. A uniform diffraction contrast across each single grain is observed in the TEM images, and the clear lattice fringes (with d110 = 0.28 nm) observed in HRTEM images reveal that well-crystallized BT nanoparticles are synthesized by the hydrothermal method. The edges of the particles are very smooth, with no surface steps. BT nanoparticles with average grain size of 90 nm, synthesized using barium hydroxide and titanium dioxide as the starting materials, show surface facets. In this case a bimodal size distribution of large faceted and smaller particles is observed. Diffraction contrast variation across the particles caused by high strains within the particles is clearly observed. The high strains obviously stem from structural defects formed during hydrothermal synthesis, presumable in the form of lattice OH− ions and their compensation by cation vacancies. HRTEM images demonstrate that surface facets parallel to the (100) and (110) planes and small islands with 3 ~ 4 atomic layer thickness are frequently observed around the edge of the particles.