Nanocrystals of a New Complex Perovskite Dielectric Ba2TmSbO6

Nanocrystals of a new complex perovskites ceramic oxide, barium thulium antimony oxide – Ba2TmSbO6,were synthesized using a single step auto-ignition combustion process. The combustion product was single phase and composed of aggregates of nanocrystals of sizes in the range 20–50 nm. Ba2TmSbO6 crystallized in cubic perovskite structure with lattice parameter, a = 8.4101A˚ . The polycrystalline fluffy combustion product was sintered to high density (∼97%) at ∼1450 ◦C for 4 h. Resistivity of the sintered specimen was ∼5 M/cm. The Ba2TmSbO6 has dielectric constant (ε) and dielectric loss (tan ı) of 17 and ∼10−4 at 5 MHz; the new material would probably be developed as a low-loss dielectric material

Optimized Combustion Synthesis and Characterization of Nanostructured Ba2RESbO6 Perovskites

Combustion of citrate complex has been a popular choice to synthesize nanocrystals of transition metal oxides in a single-step process. The amount of citric acid used for combustion is conventionally calculated based on the total valence of the oxidizing and reducing agents while keeping the equivalent ratio unity such that combustion energy is a maximum. This chapter demonstrates by employing quantum chemical calculations that the amount of citric acid could be reduced to nearly half if prepared for appreciable amounts. Transition metal oxides belong to quaternary double perovskites, with general formula Ba2 RESbO6 (RE=Rare-earth), have been synthesized as nanocrystals as examples to validate the calculations

Optimization Of Citrate Complex Combustion For Synthesis Of Transition Metal Oxide Nanostructures

Combustion of citrate complex is a popular choice to synthesize nanocrystals of transition metal oxides in a single-step process. The amount of citric acid used for combustion is conventionally calculated based on the total valence of the oxidizing and reducing agents while keeping the equivalent ratio unity such that combustion energy is a maximum. This paper demonstrates by employing quantum chemical calculations that the amount of citric acid could be reduced to nearly two-third if prepared for appreciable amounts. Transition metal oxides belong to quaternary double perovskite has been synthesized as nanocrystals as examples to validate the calculations

Recursive digital filter for fast visual evoked potential estimation and classification

Generally, visual evoked potential (VEP) estimation requires power spectrum computation. Here VEP is estimated using a recursive digital filter, which is faster and simpler to design. The method assumes VEP can be represented by a 40 Hz spectrum and the filter extracts a 40 Hz signal in the time domain, circumventing the normal procedure of power spectrum computation the normal procedure of power spectrum computation the normal procedure of power spectrum computation. Experimental results validate the method for discriminating alcoholics from control subjects

Combustion synthesis and characterization of Ba2NdSbO 6 nanocrystals

Bulletin of Materials Science344661-665BUMS

Development, Characterization, Sintering, Dielectric and Optical Properties of NdBa2ZrO5·5 Nanocrystals

Nanocrystalline NdBa2ZrO5 ·5 has been successfully synthesized through a single step auto-ignition combustion route for the first time. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the combustion product is phase pure and has an ordered cubic perovskite structure. The phase transitions and thermal stability of the nanopowder were investigated by differential thermal and thermogravimetric analyses. Transmission electron microscopy results indicated that the particle sizes are 20–30 nm. Selected area electron diffraction pattern has shown that as-prepared powder is polycrystalline in nature. The optical absorption spectra analysis confirmed that the material falls to the semiconducting range with a bandgap of ~3 ·69 eV and therefore, could be used as transparent wide bandgap semiconductor. The relative density of the sintered sample is ~96% at 1510 °C for 2 h. The surface morphology of the sintered pellet has been studied by scanning electron microscopy and the average grain size observed is ~0·7 μm. Dielectric constant (ε r) of NdBa2ZrO5·5 at 5 MHz is 29·6 and loss factor (tan δ) is 4 ×10 − 2 at room temperature

Characterization, sintering and dielectric properties of nanocrystalline barium titanate synthesized through a modified combustion process

10.1016/j.matchar.2008.09.012Materials Characterization604322-326MACH

Synthesis and characterization of nanocrystalline strontium titanate through a modified combustion method and its sintering and dielectric properties

10.1016/j.jallcom.2009.07.045Journal of Alloys and Compounds4861-2711-715JALC

Electrical and Optical Properties of NdAlO3 Synthesized by an Optimized Combustion Process

Nanocrystals of neodymium aluminate (NdAlO3) are synthesized using an optimized single step auto-ignition citrate complex combustion process. The combustion product was characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and Ultraviolet–visible reflection spectroscopy. The combustion product is single phase and composed of aggregates of nanocrystals of sizes in the range 20–40 nm. The NdAlO3 crystallized in rhombohedral perovskite structure with lattice parameters a = 5.3223 Å and c = 12.9292 Å. The absorption spectrum of the NdAlO3 nanocrystals shows characteristic absorption bands of the Nd atom. The polycrystalline fluffy combustion product is sintered to high density (~ 97%) at ~ 1450 °C for 4 h and the microstructure was characterized by scanning electron microscopy. The electrical properties of the sintered product were studied using dielectric measurements. The sintered NdAlO3 has a dielectric constant (εr) and a dielectric loss (tan δ) of 21.9 and ~ 10− 3 at 5 MHz, respectively